The problem is they cost too much compared to other units and end up filling a pseudo-cavalry/heavy infantry role, but unable to do the job as well. Mounted Sergeants cover the flanking very well (faster/more charge/one third cheaper at 300 not 900/and not designed to fight heavy infantry as you suggested) and I don't think simply being better than other light infantry really qualifies for a 900 recruitment cost

As for being better than other heavy infantry, true, but those usually cost around 5/600 maximum, so the extra 300 at least is still a pain. Especially if they're only going to sit around waiting to flank with 3/4 charge, when you could get 3 mounted sergeants flanking three units at once, or actually killing archers not just chasing them away.
LostWraith, I never thought about Spain to be honest

Always been looking at Sicily and I think you're right...but Sicily doesn't get good pike units
Oh, and Warmaster Tibs, the main reason why I use them is because they look so good
