Thessalians tend to tire and die a bit too quickly for my tastes, especially considering how expensive they are. With that said, they're not really a bad unit, as they can be very powerful.

By far the worst unit in the game is Hellenic native spearmen. They simply suck at everything. They die like flies, lose to every unit in melee combat, and rout ridiculously quickly.

As I said before, Romani consular guard cavalry are horrible. They are terrible in melee, their charge isn't that great and they die quickly. And worst of all, they don't look anywhere near as cool as any of the other bodyguards.