Trevor Penning will work at LT and RT during OTAs (OTA update: Penning moved to RT)

Oh, I know, but it destroys the argument that he's not athletic enough....now his feet may be slow because he doesn't understand how the DE is attacking him or some other reason
I agree with you. He's athletic enough and I believe the technique can be gained with time, effort and good coaching, and contact balance/ anchor forms part of technique to a large extent. I can't speak to his will to improve, his level of competitiveness, or his ability to apply learning etc... but he's not sitting at home with his feet up thinking stuff will take care of itself - he's working on his craft.