Phalanx in towns/cities are a nightmare. Just when it seems they have stopped milling and you can drop the spears, they start milling in the other direction Naturally giving the enemy time to charge with cavalry into them. I suspect the RTW pathfinding in towns is 'imperfect' for want of a better word - if they are too close to walls etc you are stuffed.
I have no such problems in the field with them. A quick jab of the phalanx button usually sorts them there.

I usually end up referring to my phalanx's by name (**** for brains) by the end of a decent city battle. Guess they aren't grunts due to natural intelligence