You've really staked out this position that Terry is unathletic, I think you're incorrect.
While I believe Terry gets high grades on shooting and basketball IQ, I also would be in the camp of low grades on athleticism.
For arguments sake, let's say we could break down NBA athleticism into three key categories: speed, explosion (bounce, vertical, separation, etc), and agility.
Speed: Terry is woefully slow. He makes up for it with his smarts, but this is a definite weakness. It's visible both on the offensive and defensive end.
Explosion: I haven't seen an official vertical on him but I can't believe it's very high. He gets very little lift on his shots or on when he finishes at the rim. He doesn't seem to recover very well on D. I don't see him create much separation when attacking the rim against college players.
Agility: I'll give him a minor plus on this as I've seen him make some savvy moves around the rim. He also is able to create shooting space with a nifty step back. He's not an NBA passer yet, but there are some moments when you can see the potential. If handles is in this category I'd give him a minus. He's too weak with the ball at times.
I'm not one to put strength as a characteristic of athleticism, but if I did I'd give a very poor grade to Terry. Sure, he might have bulked up. But I need to see how that translates to the court before I make a decision (private workouts will help). *[This is a problem in evalutaion for all of us fans since we can't actually see how his strength increase has impacted his game.]
While there are some players that can still excel with low grades in these areas, they had to do some massive tightening in the offseasons to compensate. I actually think Terry is capable of making these corrections. But it's still not enough for me to be comfortable taking him over guys like Lewis, Smith, or Nesmith.