Yeah, this sucks because my Classified Tactician is the cat's a$$ for solo farming missions and even GEs - except Assault. For that one Classified AB is probably the best.
For the Ambush assault though it might just be the be best build extant. I can run Lex on max difficulty in under 9 minutes. If they'd let me keep my stack when I ride up or down the elevator I bet I could shave another minute off that.