I must admit that I have not seen J.R. Smith play very much. I've heard things about his skills and character, and based on the opinions of several P&T posters, I'm willing to trust that the guy's a very good basketball player that could help us win games, and that his character issues wouldn't be a big problem here.
Any addition to a team is a risk/reward scenario. Even a good player can cause chemistry problems, and not always because they're a bad or evil person.
As a hopeful person, I'm wary but willing to trust that Smith wouldn't create any problems here. But I still think the Knicks shouldn't sign him.
The Knicks need continuity. Any championship team needs time and experience playing together, so guys can grow into their roles and become comfortable. So if they sign J.R. Smith, they should be thinking about not just this year, but potentially the next few years, so the guy can become part of the team.
And that would be difficult to acheive. Why? Because the Knicks are over the cap. And they don't have Bird rights on Jeremy Lin or Baron Davis. No matter how Lin or Davis end up playing for the rest of the year, you have to think that their mid-level exception next year is going to have to be used to sign the guy that's going to play point guard for them. And J.R. Smith isn't going to do that.
If they sign Smith now, he's going to play, and guys like Landry, Shump, and Toney are going to have to adjust their roles around him. But then, at the end of the season, when the Knicks use their mid-level on Lin, Baron, and/or some other point guard, there won't be any money left for J.R. Smith. He's too famous and established a player to sign for a 2 million bi-annual exception. If Lin takes the 2 million bi-annual exception, it will be because he hasn't played like a starter. And if that's the case, Davis or some other point guard must get the mid-level.
So what's the point of signing J.R. Smith, taking the risk that he could mess up chemistry, having the team adjust to him... if we don't have any way of keeping him around to grow with us?
There isn't any point. Have fun in L.A. or Minnesota, J.R.