List of unit needed to be buff
1. boat in general (boat are suppose to be powerfull for siege)
2. Lancer : I dont understand where is the utility of this unit
3. Archer/crossbowmen vs canon : am I the only one who think that its strange to see an archer able to shoot as far as a canon or that the english longbowmen shoot as far as an art?
4. knight and cavalry : IMO they arent ruling battlefield as they did historically
What do you guys mean by the Apache unit? If you mean the helicopter gunship, I've always found it a bit underwhelming.
EDIT: I forgot that melees also dont have a counter unit...
Infantry doesn't have real counter mechanised infantry can beat tanks and tanks have have a counter unit?
The balance should be: mechanised can't beat tanks but can beat anti tank weapons tanks can't beat anti tanks units balanced...
To me, musketmen should be stronger. I agree with the OP's take, especially on Ironclads and Lancers (both relatively useless), but musketmen stand out to me as mediocre. It was particularly egregious pre-patch.
Muskets were the evolution of eons of melee combat. Crude, sure, but up until very recently they were actually worse (16 vs. 18) than the earlier tech longswords. They still are no better, and you almost always are better off building Knights or Crossbows. This is one of the aspects that makes my home Civ (America) arguably the game's worst. I want to like Washington, but any type of musket unit except the Janissary or Musketeer is just too weak. The stock version is totally uncompelling.
I haven't found a real use for ironclads so I would agree that they need something just to encourage building a few.
Lancers - I always build three or four to upgrade to helis - the move - attack - move combo a real killer and lancers keep it without waiting for logistics. And MadJinn has the lancer tactic down pad - eat around the edges and they can cause a lot of pain by slash and run. Use them like a tank and they die.
Cavalry - Again, I find them fairly useful for rapid response and potential upgrades to tanks. I like to build a half a dozen or so to start building promotions. Cavalry never really dominated the battlefield, especially after the invention of the bayonet and infantry square. It could help win battles but didn't just overrun things. As it is, it will overrun art or missile units. And it provides that extra bit of killing power on the flanks or to finish off a wounded enemy so you don't see him again. Which was its role for much of history in battle (beyond scouting & raiding).
Boats - naval war in general is just underwhelming. Overall, it could use a major boost. Its gotten better but it really doesn't have much of a naval feel or, usually, much impact on the game.
Units getting varied bonus from adjacent units perhaps. Muskets will get both melee & mounted bonus for nearby pikes.The problem in no small part is that there wasn't this moment of brilliance where people stopped using swords and halberds and started using rifles. Transitional formations like the tercio are completely neglected in the Civ series despite being dominant on European battlefields in their time.
So in terms of historical accuracy Civ is getting it right, early firearms were not that dominant over melee weapons. But in a mixed formation they were a terror, and that's not really represented. I'm not totally sure how to fix Musketmen in that light, but a bonus against melee might be the best way to go about it.