His move which adds bonus damage and takes 32 mana per shot is useless, I get the extra stats instead. The explosion on impact doesn't really seem to do anything really, the damage could do with an increase.
Through War Rank 6/Cats I'm playing Regulus without items (I'll pick up Boots of Speed early) and I find Angelic Fury pretty useful both as a splash-damage grunt killer and 1 v 1 against another ranged demi, in fact I never turn it off. I put my points in this, stats, and mines and it seems to work pretty well.
Only thing is that the ultimate of AF would be alot better if it were a buff to weapon or movement speed, IMO. By the time Reg gets it he doesn't need an AOE spell. Play to his strengths.