My thoughts on this trade are all over the place. The idea of trading for an injured point guard scares the hell out of me as we have signed/traded for Penny Hardaway, Marbury, Francis, and just about every other washed up point guard you could imagine. And then there's the fact that if we wanted Rose, we could have just watched him this year and signed him next offseason. I should also mention that Rose is one of my least favorite players in the NBA (for no real good reason except that the media hype around Rose was nearly as nauseating as the hype around Steph). He was also a below average starting point guard last season. I still think that the best option for the Knicks would be to trade Melo and rebuild with young pieces around KP....and this move seems to suggest that the Knicks are still in win now mode.
That being said, Nate Duncan had a great podcast on this trade that made me feel a lot better. First, Derrick Rose is an expiring contract so if it doesn't work we clear a ton of cap space for next summer. By comparison, Robin Lopez was signed to a multiyear deal. Secondly, if we had just kept Lopez and Grant with the intention of adding Rose next summer, then the only real move we could have made next summer was to add Derrick Rose - and adding Derrick Rose to the current team just isn't good enough. Now we have a tremendous amount of flexibility. We could either retain Rose and build around Melo/Rose/KP. Or we could use Rose's cap space to sign someone else. This trade also gives me hope that we will move KP to the five and Melo to the four, which are their best positions respectively.
This trade is also a lot worse for the Bulls than for the Knicks. Not that they needed Rose, but Jerian Grant is a woeful shooter, Robin Lopez is really a 25 mpg player who isn't actually that great defensively, and Calderon is a corpse.
So all in all, it isn't the greatest move, but I'm fine with it because we have flexibility going forward. I would be very upset, however, if we compound this by doing something truly dumb like signing Dwight for 4 years at some huge salary. Our management has to start understanding that the future of this team is KP, not Melo, and we need to start getting young players that can grow with him instead of washed up former superstars that still won't be good enough to get the Knicks out of the eastern conference.