(Heavy) Cav Archers +2 attack
For the sake of theme this could be implemented as +2 arrows.
It wouldn’t have much effect, I mean most of the time Kipchaks would still be preferable over HCA, but it would feel better if FU Cuman CA weren’t completely useless.
Cuman FU CA would still be strictly worse than Magyar FU CA. (Same attack but 2 less range.)
The couple of games where someone uses Cuman Mercs to get a couple of Elite Kipchaks and then transitions into HCA could be awesome/funny.
For me the idea of giving bonus for CA to a civ that lacks bracer is just a plain mistake. I thinl both UT should be changed.
Maybe too weird, but what if Cuman Mercenaries able you to train your kipchaks in allies’ Castles?
Yes, same goes for giving HCA upgrade to civs missing thumb ring, why? 
Yeah, buffing their Cav Archers would make sense. They wouldn’t even be strictly worse than Magyars since they are faster and produced much faster (not to mention Cumans archery range discount).
That said I had another weird idea : what about Cav archers costing no wood (or just -75% wood). That would fit the UT fluff and complement Kipchaks that cost low gold. Gold tends to be more precious in the Endgame, but saving on wood still matters.
People would forget that they could do that, and it doesn’t really address how useless Cuman Mercenaries is in 1v1 games.
Interesting idea, but I think people would probably still go Kipchaks. What if Cuman Mercenaries systematically gave all teammates, including the player say 5 Elite Kipchaks every 10 in game minutes. Probably spawned at a TC, but It’s hard to say. That could be broken or kind of weird, but it would make Cuman Mercenaries more useful in 1v1 games. The best solution might just be to replace it with an entirely different tech. That’s just an idea.
Simplest idea: Keep it as it is, and allow players to replenish lost units at their normal cost afterwards.
That’s actually quite a good idea. What if it let the player replenish those ten at half cost or something instead though. The Kipchaks spawned could also be a new unit called Kipchak Mercenary instead of Elite Kipchak with better stats, but only ten of them at once. Not sure what would happen if you had 4 Cuman players on your team though.
Yes, maybe you are right. What if replaces the kipchack’s wood cost for gold, but you can train 2 kipchacks at once (48 G each) and reduce the TT to the half. It Is strong to short term because you can mass it quickly, but your gold will run out quickly too
I don’t think that people would use it though if it burned all their gold. Then the other player just has to weather the storm and then the Cuman player is in a lot of trouble. It seems a lot like Flemish Revolution to me. I would rather see this kind of mechanic implemented instead: Allow players to replenish the ten mercenaries at full cost whenever there are less than ten. (Paying for each one the way that you would normally create a unit). To make it more useful in 1v1s however you might need it to let the player replenish those ten at half cost or something instead though. The Kipchaks spawned could also be a new unit called Kipchak Mercenary instead of Elite Kipchak with better stats, but only ten of them at once. Not sure what would happen if you had 4 Cuman players on your team though.