My thoughts in terms of balance:
-Cavalry needs nerfed in some way.
As someone who pretty much only played infantry in Warband, I can confidently say I've never had as easy of a time as I do right now at absolutely demolishing entire teams as cavalry.
-Archers are way too easy to use
Given a lot of the game dev choices and buginess of the game, it's hard for me to judge if archers are too strong, but they definitely feel very easy/amazing to use. Similarly to cavalry, if I just want to reap kills right now, I just go archer and it feels very low effort to get some ridiculous K-D and/or win rate. Just jumping into MP and not testing anything in SP, it felt almost trivial to headshot people now.
With how great archers and cavalry are, there really doesn't feel like there are any reasons to go pure infantry.