I think chemistry is a very underrated component of a team. Melo has a questionable ability to fit on any given team. Not saying he's locker room poison, but there's little evidence he's the glue. I have a big problem with trading out three rotation players for him -- I think that upsets the lineup too much.
Add in the ~$20 million of lost cap space this summer and draft picks, it's a no-brainer (to reject) to me.
The draft picks sink it for me. I'd do AB+Zeller+AJ and try to win small. I wouldn't trade AB (who I think is extremely valuable in today's NBA) along with 3 fairly useful draft picks for an aging superstar with 1.5 years left on his deal.
Saltlover hit the nail on the head though. My reluctance to move multiple assets for Melo is mostly due to the likelihood of him declining in effectiveness sooner rather than later, and his reputation (deserved or not) for diva behavior. I'm fine with the cap space as I think it really only costs us one summer of FA because Melo will likely opt out his last year.
I'd risk AB+filler on being title opportunists for a couple of years. I wouldn't give draft compensation in addition.
I'd prefer we get Melo in a dump for AJ, Zeller, JJ and our 2018 pick. I think NYK will want a core guy to flip and that is where I either sub in AB for the 2018 pick or walk away.
Alternatively, I'd take on Reddick to facilitate Melo to LAC.