So far in this version of the beta I have found the rook and regulus to stand out from the rest of the bunch.
The rook simply has to much HP and to much attack. Boulder Roll + Hammer slam is sick in this build the area of effect damage hammer slam deals out is immense. I would like to see something changed to bring him down to the level of the other demigods or something done to the other demigods so they can compete with him.
Regulus's range is to big. Hit and run with regulus is insanely easy to accomplish. Anybody can sit and shoot a few arrows, run away when being approach by a melee demigod then proceed to follow the melee demigod after the melee demigod retreats from the tower fire. Don't even get me start on snipe. Snipe is a extremely over powered. It hits across the map for great damage and the cool down is not to bad.
The other major problem with balance is the Unclean Beast. The Unclean Beast is pretty much unplayable in this build. In 1v1 he has no chance against the other demigods in his early levels. He has no area of effect damage to take creeps out. For example: going against Sedna is particularily difficult because her Yetis have the same HP as you do. Getting hit by Sedna for 120 and 2 yetis for 35-40 damage isn't much fun.
Anyway thats my 2 cents for now.