For me, TD's athletic ability isn't in question...the kid is talented. As I've said many times, I think his success is directly correlated to the development of the OL.He doesn't have to be tough to take down. He only needs to take what's there and then get on the ground. If he makes the right read and gets 4-5 yards when it's there (he often got more than that this past year), that'll keep the defense honest and keep things open for the other aspects of the offense. He should only need to run as a change up, not be the hero like Dungey was forced to do too often.
Imagine TD standing in a clean pocket like Tua had most of the year. He'd be throwing darts all over the place.
Now...imagine TD playing behind last year's OL where his improvisational ability is forced to the forefront. Can he be effective in this scenario? Hopefully the OL's development makes all this moot.