I wanted to take a look at where I think the current Skirmisher line is at. Skirmishers have received numbers changes in the last few years, so where have they settled?
I'm going to note the stats of the unit below, which includes its skirmisher doctrine bonus and the "normal" number of accuracy promotions for a unit of its era at best.
I'll use the standard:
A - Good Unit
B - Decent Unit, a tweak could be done.
C - Really bad.
Skirmisher - A
CS: 16.8
RCS: 14
The skirmisher is good for a few reasons. Stat wise, its superior to the c bow, it has impressive CS, able to stand up to a Formation I spearmen and horseman, and does alright against swordsman attacks.
The other reason is tech tree. For players doing a mathematics rush (a common opener), this unit gives them a solid military unit that can keep their civ safe against more militaristic civs.
Its a good unit with a good niche in the game, just depends on what you are going for with the tech tree.
Heavy Skirmisher - B
CS: 21
RCS: 27
On paper, the unit boasts an impressive RCS, but in reality it has a lot more counters than the Skirmisher face. Formation II pikes or Cover II longswords will be more common on the field and can tank the pain... but ultimately its the knight that puts the unit to bed. The knight is such a good solid stable unit at this phase in the game that it guides your desire for horses that way.
I also find that most of my builds want chivalry before physics. Doesn't mean I want to skip physics, and there are some civs where I go that way first, but chivalry is the staple, and so knights tend to come out sooner than heavy skirmishers, and therefore be more relevant on the battlefield longer.
Cuirassier - C
CS: 32.2
RCS: 43.2
Holds the title for the most unpronounceable unit name for me
Tech tree wise the unit is in a decent place, a strong warring player gets a lot of toys with this tech, so a decent incentive to use it.
Stat wise, the main thing is that CS for the unit is starting to lag behind its fellow units even in open terrain. Even a tercio can do good damage to this unit, and once fusiliers come out (which is just around the corner), the unit struggles to avoid taking lots of damage while dealing effective damage.
I generally find lancers a bit more durable and flexible, still able to handle cannons and field guns but with more terrain versatility.
So ultimately I don't find a real niche for this unit.
Calvary - A
CS: 46.2
RCS: 69.7
I would argue that the Calvary is the apex of the skirmisher line. For one, its a nice spot in the tech tree, as military science is a major waring upgrade with the ability to crank out 3 promotion units. This also means that not only do you get the unit, but you may get the extra push of a promotion advantage over opponents going more north side of the tree.
Two, at this point in the game, rough terrain is starting to fade quite a bit. A lot of forest and jungles have been removed by now, leaving a more open field on which to war, which gives it a wider range to use. Also railroads help skirmishers a lot with the ability to dart in and out. Calvary are a strong counter to the ironclad spam that is common at this point in the game, comparable to field guns in terms of damage to naval, and with the ability to cycle them in and out to avoid ranged naval fire.
Stat wise, the cavalry is really good. It has an excellent attack against field guns but most importantly.... Gatling guns. Its one of the few units that can go toe to toe with massed g guns and come out on top if the terrain is favorable.
The only real competition for cavalry is agribusiness, as people may want to trade in their horses.... so that depends on the civs abundance of pasture and farms.
Light Tank - C
RCS: 88.4
CS: 72.8
On paper, the light tank looks like a decent unit. Its a decent tech tree spot, and the fact it uses an alternate strategic resource compared to iron and oil should in theory mean it will always have a niche.
But this is when experience comes in, and in my experience, light tanks die easily and often. The rise of artillery, both for the range and the ability to put splash damage as a given really dampers the skirmisher line in general. But aircraft are the nail in the coffin....if a light tank is ever resting on rough terrain....its dead. And even if its in open terrain, its still often dead. Its possible to focus so much ranged fire on a unit at this era of war, and the light tanks are expensive units with no terrain defense and not a high enough RCS to really hold out (compared to a tank that has an effective 116 CS on defense).
The unit just doesn't have the durability to stand up to its modern contemporaries, and then once tanks come out and the melee line sees its resurgence, its hard for the light tank to compete.
Lastly, the light tank is also decently expensive compared to machine guns and planes, and generally don't have as much value.
Helicopter Gunship - C
CS: 60 (90 vs tank)
RCS: 97.5 (135 vs tank)
On the one hand, the gunships combat effectiveness is pretty minimal. Even its anti-tank stats aren't that impressive when you consider the tanks defense bonus (modern armor is often 155 for context). So they really aren't a great counter for tanks like they look to be.
Tech tree wise they are in a sad place, the simple truth is, once you have Advanced Ballistics, you just don't need mobile tactics most of the time, there are better areas to spend my science on until I'm ready to go deep in the tree.
Then add in the Air Supremacy promotions, and fighters just wreck the pants of this unit.
That said, the ability to hover off coastlines and hit naval units is useful, the units hover does give it some niches in scouting and pillaging (though of course the scout line do these pretty well as well).
I generally find 1 or 2 gunships have a use, but beyond that I never go them.
Thoughts on Improvements
Heavy Skirmisher - No changes. Though the unit is a bit weak, I think its more that its simply time for Knights to shine. They aren't terrible units, and as upgrades from skirmishers they are serviceable.
Cuirassier - Probably just a modest CS update (leave RCS alone). The unit does respectable damage its just a bit too fragile to warrant good use.
Light Tank - I would consider giving it the same armor plating upgrade that other tanks get, the unit is just way too fragile at the moment, it needs durability to be at all competitive. I would also give it 5 speed at base. This thematically makes sense (the "lighter" tank should at least as fast as the heavy tank that follows it), and would give it a little more maneuverability and ability to get out of hot zones.
Gunship - Remove the bonus vs helicopters for air supremacy upgrades...the upgrade is still solid (you get it for aircraft anyway), and that way helicopters aren't blown up just for existing. I would also increase their speed to 8, if the GDR can get that speed I think its fine for the helicopter to have it. I still think they will have limited use, but it would be something.
I'm going to note the stats of the unit below, which includes its skirmisher doctrine bonus and the "normal" number of accuracy promotions for a unit of its era at best.
I'll use the standard:
A - Good Unit
B - Decent Unit, a tweak could be done.
C - Really bad.
Skirmisher - A
CS: 16.8
RCS: 14
The skirmisher is good for a few reasons. Stat wise, its superior to the c bow, it has impressive CS, able to stand up to a Formation I spearmen and horseman, and does alright against swordsman attacks.
The other reason is tech tree. For players doing a mathematics rush (a common opener), this unit gives them a solid military unit that can keep their civ safe against more militaristic civs.
Its a good unit with a good niche in the game, just depends on what you are going for with the tech tree.
Heavy Skirmisher - B
CS: 21
RCS: 27
On paper, the unit boasts an impressive RCS, but in reality it has a lot more counters than the Skirmisher face. Formation II pikes or Cover II longswords will be more common on the field and can tank the pain... but ultimately its the knight that puts the unit to bed. The knight is such a good solid stable unit at this phase in the game that it guides your desire for horses that way.
I also find that most of my builds want chivalry before physics. Doesn't mean I want to skip physics, and there are some civs where I go that way first, but chivalry is the staple, and so knights tend to come out sooner than heavy skirmishers, and therefore be more relevant on the battlefield longer.
Cuirassier - C
CS: 32.2
RCS: 43.2
Holds the title for the most unpronounceable unit name for me

Stat wise, the main thing is that CS for the unit is starting to lag behind its fellow units even in open terrain. Even a tercio can do good damage to this unit, and once fusiliers come out (which is just around the corner), the unit struggles to avoid taking lots of damage while dealing effective damage.
I generally find lancers a bit more durable and flexible, still able to handle cannons and field guns but with more terrain versatility.
So ultimately I don't find a real niche for this unit.
Calvary - A
CS: 46.2
RCS: 69.7
I would argue that the Calvary is the apex of the skirmisher line. For one, its a nice spot in the tech tree, as military science is a major waring upgrade with the ability to crank out 3 promotion units. This also means that not only do you get the unit, but you may get the extra push of a promotion advantage over opponents going more north side of the tree.
Two, at this point in the game, rough terrain is starting to fade quite a bit. A lot of forest and jungles have been removed by now, leaving a more open field on which to war, which gives it a wider range to use. Also railroads help skirmishers a lot with the ability to dart in and out. Calvary are a strong counter to the ironclad spam that is common at this point in the game, comparable to field guns in terms of damage to naval, and with the ability to cycle them in and out to avoid ranged naval fire.
Stat wise, the cavalry is really good. It has an excellent attack against field guns but most importantly.... Gatling guns. Its one of the few units that can go toe to toe with massed g guns and come out on top if the terrain is favorable.
The only real competition for cavalry is agribusiness, as people may want to trade in their horses.... so that depends on the civs abundance of pasture and farms.
Light Tank - C
RCS: 88.4
CS: 72.8
On paper, the light tank looks like a decent unit. Its a decent tech tree spot, and the fact it uses an alternate strategic resource compared to iron and oil should in theory mean it will always have a niche.
But this is when experience comes in, and in my experience, light tanks die easily and often. The rise of artillery, both for the range and the ability to put splash damage as a given really dampers the skirmisher line in general. But aircraft are the nail in the coffin....if a light tank is ever resting on rough terrain....its dead. And even if its in open terrain, its still often dead. Its possible to focus so much ranged fire on a unit at this era of war, and the light tanks are expensive units with no terrain defense and not a high enough RCS to really hold out (compared to a tank that has an effective 116 CS on defense).
The unit just doesn't have the durability to stand up to its modern contemporaries, and then once tanks come out and the melee line sees its resurgence, its hard for the light tank to compete.
Lastly, the light tank is also decently expensive compared to machine guns and planes, and generally don't have as much value.
Helicopter Gunship - C
CS: 60 (90 vs tank)
RCS: 97.5 (135 vs tank)
On the one hand, the gunships combat effectiveness is pretty minimal. Even its anti-tank stats aren't that impressive when you consider the tanks defense bonus (modern armor is often 155 for context). So they really aren't a great counter for tanks like they look to be.
Tech tree wise they are in a sad place, the simple truth is, once you have Advanced Ballistics, you just don't need mobile tactics most of the time, there are better areas to spend my science on until I'm ready to go deep in the tree.
Then add in the Air Supremacy promotions, and fighters just wreck the pants of this unit.
That said, the ability to hover off coastlines and hit naval units is useful, the units hover does give it some niches in scouting and pillaging (though of course the scout line do these pretty well as well).
I generally find 1 or 2 gunships have a use, but beyond that I never go them.
Thoughts on Improvements
Heavy Skirmisher - No changes. Though the unit is a bit weak, I think its more that its simply time for Knights to shine. They aren't terrible units, and as upgrades from skirmishers they are serviceable.
Cuirassier - Probably just a modest CS update (leave RCS alone). The unit does respectable damage its just a bit too fragile to warrant good use.
Light Tank - I would consider giving it the same armor plating upgrade that other tanks get, the unit is just way too fragile at the moment, it needs durability to be at all competitive. I would also give it 5 speed at base. This thematically makes sense (the "lighter" tank should at least as fast as the heavy tank that follows it), and would give it a little more maneuverability and ability to get out of hot zones.
Gunship - Remove the bonus vs helicopters for air supremacy upgrades...the upgrade is still solid (you get it for aircraft anyway), and that way helicopters aren't blown up just for existing. I would also increase their speed to 8, if the GDR can get that speed I think its fine for the helicopter to have it. I still think they will have limited use, but it would be something.