If you want the most effective blapper experience, you want Electric Manipulation. All the attacks are juicy, damage aura built into the sustain, Shocking Grasp can be procced to the nines to have incredible DPA. More importantly, it's a separate damage type from Psi blast. Very important for some high end enemies, like Tarantula Queens who have a lot of psi resist.
Sonic is another option. While I haven't played it myself, from a glance it has all you need. Good melee and a good PbAoE. Other picks could be Fire, Ice, or maybe Atomic which has some built in status resist.