And also, centaurs. You can't forget about them; their last shot is worth a lot.
I don't understand, so you think barbarians are the weakest race?
It's just that barbarians aren't my preferred playstyle. I like archers and mages, and those units are weak in Stronghold. Thunderbeasts and Ogres cast spells, but it's not very significant.
The Cyclops is a really powerful warrior, especially with its area-of-effect attack.