He is wise to hold off on the VP pick until the convention. He needs the drama of the selection to bring in ratings and viewers. It must be unique and exciting. The goal should be to offer up an exciting convention that will draw in watchers—musical groups, right wing Hollywood people, Party stalwards and such—Bush and Mittens not coming might be a good thing. Who wants to hear them?
It's all part of the strategy to make Hillary and the democrats look dull, old, and decidedly "uncool" while Trump is the exciting new Future of America.
Count on it. This is all part of a real strategy, the like of which Hillary and company will be completely unable to deal with.
Good points and good post, thanks!