I think spearmen and pikemen can exist together without too much overlap. Spearmen can be decent anti cavalry with the ability to withstand enemy volleys, while pikes can be the real cavalry stoppers, albeit at the cost of being target practice for archers.
Yes, but this touches on another point which is the behavior in formations and the shield wall. Currently the front line of the shield wall will include units without shields which is not how it should be. Currently I rarely use unshielded troops as you have to do to much micromanagement to get them to survive until the melee mosh pit. I would love to simply order my infantry into a shield wall and the heavy shielded infantry will take the first two lines while the shock troops and skirmishers will stand behind them and advance orderly towards the enemy.
Additionally I would love to get a better handle on skirmisher infantry units. Currently they also require a lot of micromanagement to use them rather well. IMHO it really depends where things shall go. If the AI is rather well implemented then you can simply shove them off to the AI and run hay wire in the battle field but as long as the AI has its quirks micromanagement is all that you've got.