Most Hated Unit -

Pre-1.2 = Desert Axemen with their ridiculously high bare-chested armour rating.

Post-1.2 = Tie: Swarming overpowered overmanned Desert Cavalry and any chariot fielded by any faction under any circumstances. Chariots were outdated by 300 B.C., and for a reason. All you had to do was kill/maim ONE of the horses (a big target for archers, javelineers and spearmen alike) or put a stick through one of the spokes of the chariot cart wheels, and chariots would wreck all over the place. Ever seen "Ben Hur"? Plus, chariots were virtually useless on anything but flat, open ground. Honorable Mention: anything else in the Egyptian order of battle.

Most Ridiculous Unit -

Tie: War Dogs (come ON, and ENTIRE UNIT of DOGS?) and Head Hurlers (no comment necessary).