You're exactly right. We really have two options to build a contender. Either trade Melo for DWill + Morrow, completing the roster to run the system the current roster and coach are meant for....OR....build around Melo.
To achieve the 2nd option, we would need to build a roster similar to the 2000-2001 76ers lead by Allen Iverson. Surround Melo with all great defenders and hustle players. We would need to get a SG like Tony Allen, a PF like Serge Ibaka and a PG like Raymond Felton. We would also need to fire D'Antoni and hire a coach similar to Larry Brown's style. Someone in the Thibodeau or Scott Brooks mold. Probably a 6th man who can explode for 25 pts on any given night and hit the outside shot would be needed as well. I suppose JR Smith could fit that role nicely.
There you have it. Which scenario would Knick fans prefer?
Those that believe D'Antoni's system, particularly with the improved defense, can't win a championship are out of touch with reality. And those that think just adding a new coach will make this team contenders are even more out of touch. And those that think just getting Phil Jackson will bring us a championship do not know the Triangle, or Phil Jackson, very well. Phil would still need a PG (albeit different from the one the current system needs), a quality SG that can defend and hit the outside shot, and a back-to-the-basket PF or Center.