He also dismantles the left so easily and so well. He's an important part of the movement at this point because of all that.
Absolutely.
I just don't think (for the reason I gave) that he will be Trump's running mate. I do believe though that Vivek will serve in a very high public-exposure role in the campaign and new administration.
A running mate mustn't distract attention from the presidential candidate, whether intentionally or not. The person selected as VP candidate must bring value...and absolutely no risk. Vivek brings the risk that he is so good that he will suck oxygen out of the campaign by diverting attention to himself and away from Trump.