There are way too much infantry at this game, so the mod is tried to be balanced around them. This, I can understand to some degree. Infantry, by it's nature, is the least useful class in battle. Ranged can shoot from afar, cavalry has lots of space to outmanuever infantry. The only thing that an infantry can do is, to get close to the enemies to actually do something. Even then, infantry is at it's higher risk during that time; kinda encouraging him to play more safely somehow.
This is one of the contradictions I guess. Battle gamemode is a nightmare to infantry. It always been like this, even in other mods for me. I picked archer/cav for battle mostly, and infantry/archer for sieges mostly. When I try to play as cav in siege, I don't expect to be the dominant class. Same goes if I play as infantry in battle. It is both frustrating and challenging, in a good way somehow. That is one of the reasons why I choose siege gamemode when I want to bash some skulls, and choose battle-gamemode when I want to play differently.
What I don't understand is, why you keep insisting on playing battle as infantry and suggest that the gamemode should be balanced around it? Changing the gamemode to something else (for example, with earlier MoTF spawns, is one of the brilliant ideas) can be a better solution. Or you are free to change your class whenever you want to whatever you want. Wanna play battle? You fail as infantry and see cav/ranged as easy mode? You can simply change your class. There are ways for a cavalry to be useful in siege and for an infantry to be useful in battle, especially with the current balance.
I must also confess that I mostly suck at battle-gamemode. But I didn't really see much teamplay in it from other players. People are just randomly roaming around. For me, it is a much more gamemode with an objective in mind. One of the most obvious examples is, protecting your fellow infantrymen from cavalry as a spearman. I see Infantry's objective is to be anvil, not hammer. At least in the starting phase. If you don't want to be an anvil, pick a "hammer" class.