Another exit velo thread, yes I can't resist... For the millionth time high exit velo indicates potential it does not guarantee success. Low exit velo however does pretty much guarantee failure. 86 is not low, just isn't high. If this player had other things going for him he could be D1. Again as PG stated assuming these numbers are peak off a tee. Average EV in game brings consistently squaring the ball into the equation and that is in the long run much more important.
Bob, I am puzzled at some of the things you say. You can not hit home runs with below average exit velocity. And although Olerud's swing may look effortless I assure you his barrel was moving quite quickly and bat speed + squaring it up = high exit velo and home runs. No player can survive in MLB without high EV.
So in fantasy land (to answer the question) if all other things are truly equal the difference between 86 and 96 would be absolutely gigantic.