Maybe we should wait at least a few more years before debating this. Yes, this is a very successful start to his head coaching tenure, but it's far too early to tell what the long-term impact will be.
I will indeed say that if TJ can sustain this level of play and build off of his early success, then yes, he's in for a very successful career at least (and yes, likely, if what he's accomplished year-to-year so far is the norm, he's at least in the conversation for greatest of all time). But it needs to be noted that, while future success may feel "inevitable" after a hot start, it's not (as has been proven by many college athletic programs all over the US).
I believe in TJ and I hope he continues to build off of what he has done so far. But I feel that it's not fair to him or the coaches that have come before him to start deciding his legacy before it's had a chance to play out. We need to give him a few more years to build his legacy and only then can we begin to have this debate without guessing how his tenure will impact the future of the program!