I agree with @Heroe. If all Units/Spells/Items were equally good, you wouldn't know which to choose. It would just create unnecessary confusion. This way, if you want to ease it for yourself, you can choose stronger units and if you want a challenge, you can choose weaker units.
By the way, I still haven't seen a unit in KB that totally suck. Even the worst of them have at least some advantages.
May the Devs keep up the good work in Corssworlds as Well.