True, my favorite EA build is not softcapped on neg def without an Energy Drain. It is capped for S/L/E/F/C with no drain.
I havent bothered to build for any PSI protection, if I have any its incidental. And of course I need to keep an Eye out for Def Debuffs, which you don't have to do on SR.
NIN numbers are slightly lower than SR aren't they? So would take more IO's. They do get AOE defense MUCH eariler though. You could have your basic Melee/Ranged and AOE shields all running by level 2 if you wanted. I guess it depends how much Exemping you plan on doing. You can solve the SR AOE problem by playing Stalker or Brute instead though I suppose.
NIN has the most tools though, HEAL, End recovery, Active mitigation, Stealth, Crit buff, Movement buffs. But you lose the Recharge buff. Which would be a pain to build around since I like perma hasten.