No, and for a couple of reasons.
1) Hes a good player, but hasn't shown that he's good enough to lead a team anywhere of much significance. Brooklyn were stacked last year and he never got then that far, and his former hawks were famous for being permanently stuck in second round limbo, despite also being pretty stacked a few of those years.
2) If we take that contact of Brooklyn it increases the chance that they might be able to make a move to improve their team as s result of the improved financial flexibility. That means more chance that our draft picks will lose value.
This.
no way JJ makes us a contender. not even close, he might, however, artificially boost our win total (i say artificially as he isn't going to be on future teams with our young guys, once they're developed), hurting our chances at getting a better pick in the draft.
this would be the sort of short-sighted move that keeps badly managed teams like the knicks mire in mediocrity year after year.
in fact, the nets using cap space on JJ is one of the prime reasons they aren't a true contender to begin with, they've had no flexibility for several years now, and they traded young talent/picks for a team that isn't good enough to win it all.
us getting JJ would be duplicating the same mistake that sunk both the nets and hawks.