Don't like a system where the big markets are getting the same draft picks as teams like the lolcats. The draft is a way to even the palying field for teams that have no chance in free agency (like the Jazz). If a team like the Lakers are still the hottest free agency destination AND they're getting top picks....****.
It could also turn the draft into free agency, in a sense. If you're a superstar like Wiggins and you see Milwaukee has the top pick in the draft this year, and the Lakers have it next year, you don't think there's a chance he might stay another year so he can go to LA?
These are just a few reasons. I wasn't sure how to feel about it at first, but it didn't me long to become very against it after hearing further analysis. There's a reason why so many teams are against it (hint: they aren't big market teams).