I went with body mastery for FA and LBE on mine so I could get phase. Regens with Phase very rarely die in pvp. Not to mention with enough recharge, you can spam LBE with the achilles proc in it to make your melees hit even harder.
Woo another fireblaster regen scrapper! Haha as if heroes don't have enough of those broken pvpers
Right now I have an in-game build for weapons mastery with concealment, but I've been hearing a lot about blaze mastery with leadership. I messed around in Mids and came up with this build for Blaze Mastery. Critique and elaborate