Didn't they put most of that stuff back into TTT2? So what were the complaints for TTT2 then?
Tekken has always sold well in the US, at least for the previous generation. Tekken was the highest selling fighting franchise for a really long time (not including Smash).
T6 sold very well, its now at 3.6 million worldwide. TTT2 on the other hand has probably the worst singleplayer content of any tekken. They really focused on improving the training mode and the online with TTT2, and the sales suffered because of it. The wiiu version is the only version with decent singleplayer, but who cares about wii u fighting games.