Monarch player here, recently working to improve my warmongering skills, particularly with the popular tactic of rushing to Liberalism and starting a renaissance war against AIs with longbows.

In the past I had used rifles/trebs and found that I would have to steadily reinforce my trebs from losses to longbows. But my most recent game I went for steel first to use maces/cannons and found CR2 cannons had great combat odds and as a result hardly lost any cannons. Of course, CR2 and CR3 maces against red-lined longbows mean no losses, either.

So is siege > all?
Or is there another combo equally or more effective? Will I need rifles to wage renaissance wars once I move up to Emperor+?

Map dependent. AI cuirassers in force will utterly screw your stack if you rely heavily on the cannon line. Rifles are much better there and honestly, how much collateral do you need before your rifles start having favorable odds against longbows?

On water maps, however, cannons are much more appealing because you will pretty much need chemistry already for frigates - steel is a tech away (assuming you have iron for cannons and frigates!).

Completely neglected in this discussion is cuirassers/spies or just a cavalry push. Cuirassers are faster than either cannons or rifles (both in terms of move speed AND tech!), and have the strength to match cannons...not easily countered by any unit until the AI gets rifles. In force, they and cavalry are incredibly dangerous.

So for land fights against toughish opponents, go rifles, against land opponents that aren't THAT strong, go cuirassers or cavalry, and on water maps or intercontinental attacks go cannon (and shred counterattacks with city garrison troops)

Map dependent. AI cuirassers in force will utterly screw your stack if you rely heavily on the cannon line. Rifles are much better there

I am operating under the assumption that the AI was still using longbows. Heck, even muskets. Assuming cuirassers, formation pikes should keep your stack safe (later upgradeable to rifles), but cuirassers will certainly make defending border cities and new conquests problematic without rifles.

and honestly, how much collateral do you need before your rifles start having favorable odds against longbows?

It's not about giving your rifles favorable odds, it's about constantly making new trebs to replace the suicide ones. I guess I find having to wait for reinforcements to significantly slow my advance. Perhaps building up significantly more trebs is the way to go?

On water maps, however, cannons are much more appealing because you will pretty much need chemistry already for frigates - steel is a tech away (assuming you have iron for cannons and frigates!).

Definetly.

Completely neglected in this discussion is cuirassers/spies or just a cavalry push. Cuirassers are faster than either cannons or rifles (both in terms of move speed AND tech!), and have the strength to match cannons...not easily countered by any unit until the AI gets rifles. In force, they and cavalry are incredibly dangerous.

Have you found this to be viable with the 3.17 increase to city revolt espionage costs?

So for land fights against toughish opponents, go rifles, against land opponents that aren't THAT strong, go cuirassers or cavalry, and on water maps or intercontinental attacks go cannon (and shred counterattacks with city garrison troops)

like meinteam says, it is situational. It depends on what your opponents will have.

Cannons and macemen are much better against inferior foes. Because, cannons can defend against anything with 12 strength, and per unit, cannons do more damage than riflemen, so you'll be able to fight through armies like paper. The cannons are also invulnerable to collateral damage, so a stack of riflemen may get taken down by enough catapults, but this never will happen with cannons, further making them godlike against low tech armies.

Riflemen still are quite good at taking out inferior units, although you will need a bit more units and take a bit more losses, or at least will go slower because cannons eliminate city defenses so quick.

Production wise, it is easier for a high pop, low hammer civ to produce riflemen through drafting. For a high hammer civ, cannons are just as easy to build, and require less beakers to get to them.

Levgre, that's a good point about cannons and low-tech opponents. It's pretty funny to see my cannons acting as stack defenders.

Something else about using maces is the ability to upgrade them to CR3 rifles. While this might not be be necessary, in my current game it looks like Willem will get infantry before me by the time I get around to attacking him. I assume that CR3 rifles will do just fine against red-lined infantry, while machine guns should make excellent stack and city defender against infantry.

If you have cannons, they're probably your CR units. Upgrading CR maces to gunpowder troops was pretty standard I thought.

Note that while teching to cannons, an AI that grabs gunpowder/MT can often do so surprisingly quickly. This window isn't as large as one thinks but of course if you get there in time to truly exploit it the cannons will flatten everything. Just remember that formation pikes are not particularly easy to attain for non-AGG/CHA (needing 10 XP), while shock cuirassers need 5 xp and tend to match them. Another problem is, of course, the collateral inflicted by cuirassers on cannons if they hit your stack. Granted, the AI isn't great at this, but it could so happen that 1-4 cuirassers attacking you survive, and now all your cannons are damaged down to 8-10 strength. That's a problem and a big one - combat maces, spare knights, more cuirassers, even muskets are a threat then. If you want to advance decently you're better off getting steel and hitting BEFORE they can field cuirassers (or merely picking a target that doesn't have either iron or horses since they need both).

Cuirassers are a bit weaker in 3.17 with the EP cost raise but I don't think it would cause you too much trouble unless you tried using them on Deity or something. Cavalry don't even need spies and are basically a 1 tech variance from rifling and CHEAP upgrades from cuirassers!

If you're assuming a strong tech advantage over your opponent to the point they are using longbows or maybe muskets, then it really makes no difference which you choose. Personally I have been taking the steel route followed by MilSci. Chemistry unlocks both of these. With either an Agg or Pro leader you can give Grenadiers C1/C2/Formation which is adequete stack protection vs Knights, Cataphracts, Curassiers and even Conquistadors. Yes rifles are a better counter for mounted, but require a number of fairly expensive techs to Research. By that time your cannon advantage is pretty much gone.
The cannon/gren approach also allows you continue the assault a bit longer. As your maces get to CR3 they can be promoted to grens. CR3 grens really have no counter until Cav are on the scene and as you slowly lose cannons from attrition attacking top defenders and hill cities you need less collateral for Grens to have strong odds. During the war you can research MT or rifling to further strengthen your army.

If you have cannons, they're probably your CR units. Upgrading CR maces to gunpowder troops was pretty standard I thought.

Note that while teching to cannons, an AI that grabs gunpowder/MT can often do so surprisingly quickly.

This is true, more so on higher difficulties of course...

If you do get cannons and can beat people around with impunity, there is always the chance of being able to take away their source of horse. Or use spies to get rid of it until you reach the source, or for just a limited amount of time while you take out some of their cities (if their production is destroyed the few cuirassers aren't going to be very scary, and could be countered by a few elephants and/or pikemen.).

Cannons are actually much better on tech parity. If the AI has rifles, you can still take them with Rifles+(a lot of) cannons. If the AI has longbows, either will do fine, but against an opponent who is not protective and doesn't have many hill cities rifles would probably be quicker (no need to bother taking down defences at this case). Cavalry would be even better under this scenario.

One thing I would be interested to know is if a CR 2 treb causes the same collateral to a defending stack as a CR 2 cannon? I assume they do, but it would be nice to have this confirmed :P

I use the cannon route, I think you KO city defenses much faster (esp if city has walls/castle) and suffer far fewer losses of siege units. If the AI manages to trade/tech Rifles early in the war the treb losses can be much worse, also you can quickly add Grenadiers to your arsenal.

Also having the Ironworks available earlier is a nice side effect.

i used to say rifles every time, but recently i have come to prefer grenadiers, later supplemented by cannons.

I usually go for Rifles for one big reason: Drafting. While I'm teching there I'll build 12+ trebs. Then it's just a few turns to draft 15 or so rifles, and I'm off to war. Typically I only lose two or three trebs per city before they start winning, so I can replace them fast enough.

I usually try to get both rifles and cannons, then find whoever has no rifles and pound them.

Also, it is sometimes fun to get rifling, draft a bunch, declare war against someone whose stack you can see coming; kill their stack a defensive war (especially nice if they have a lot of knights) while teching to steel, build or upgrade cannons, then invade when they have a lot of WW and not so many troops and you have rifles and cannons.

I have less success invading with rifles + trebs because I often forget to spend enough EP, and without it, their castles = trouble (trebs very slow to take down walls)