I'm having kind of the opposite experience. I've managed to get full IO / superior AIO sets and the build is definitely solid. However, it feels clunky for me even with perma hasten and plenty Luck of the Gambler slotted. The AoE clear just doesn't really compare to what I was getting on a Spines/Fire brute with equivalent investment. The single target is decent, but for that I felt my Illu/Rad controller outperformed it.
What kind of end-game content should I be looking to do solo that this build excels at? So far, it feels like a jack of all trades master of none kind of deal.