As for the M36, as you pointed out, its USF's only source of late-game AT. Why not change this? It's been suggested several times (there are other threads, but I'm linking my own) that giving USF a "medium TD" (for example, a massively adjusted non-doc M10) would fix several problems at once:
I think this would be ideal, but it also might be too late in the games life for that type of change. If they did it though they could potentially make the Jackson 480 HP again and make it a true glass cannon