I'm trying to remember which TM's we lost in the generational shuffle, but the only one I can think of is Work Up.
Usually if we get new move tutors they tend to draw from TM's we had but lost at some point (although there are big exceptions). But based on the data mine I doubt there would be many more (perhaps just two to replace dark pulse and sleep talk).
I find an easy way to find which TMs we lost is just to go to Mew's XY Serebii page. Judging by that, we lost...
Telekinesis, Work Up, Pluck, Ally Switch, Focus Punch, Water Pulse, Bullet Seed, Shock Wave, Secret Power, Brine, Endure, Silver Wind, Avalanche, Captivate, Natural Gift, Whirlpool, and Defog (COME BACK TO US BBY). Three of these are confirmed to be tutors in ORAS. (y u no defog)
This doesn't include moves that have lost their TM status but were in BW2's tutors, such as Iron Tail and Dragon Pulse.