Egypt get my vote as the worst faction.Just so unrealistic to take apart Roman Cohorts with those Axemen with no bloody armour.The Numidians are the most frustrating i think but i did enjoy the challenge.You need to rely on a lot of mercs to get anywhere but once you capture a few developed cities the Numidian Legionaries make adequate line infantry backed up by archers and flanked by barb cav.It's fun to have to use tactics again.
I agree that the Gauls,Britons,Dacians and Germans are boring and the same with the Greeks for lack of variety but not just as annoying as the damn Egyptian with their invincible units.In RTR they are replaced with the(correct) Ptolemic Empire and are more enjoyable to play with and against.