I posted this in a comment, but I'd like some more widespread opinion on it. The next paragraph is copied directly from that comment, and then after that I have a few additional thoughts.
If there’s one change out there I’d be willing to make, it would be to trade for Ray Allen. I’ve thought about this a while, and he would probably be perfect either as the starting 2-guard or as the sixth man. I was screwing around on the Trade Machine and I couldn’t really make it work money-wise, but I didn’t get too creative, so whatever. Anyway, the Celtics seem willing to entertain trade offers and they might be willing to take back Toney Douglas (not JUST TD obviously, but he would definitely be part of it). If they can get Toney back to basics, he might thrive playing off the ball with Rondo, and they’d have him and Rondo to begin building with after KG and Pierce are gone. As for the Knicks, Ray’s still money from behind the arc and would help spread the floor well. Plus, he’s a fairly committed defender and would be another championship winning presence in the locker room. The Knicks would have his bird rights too, so he could come back next year without hamstringing the quest to resign Lin. I dunno, I think Ray Allen is pretty much a perfect fit. BTW, I know the easy retort is that the Celtics won’t trade him in the division, but I think if Grunwald were to make the best offer, Ainge would take it.
Hvino mentioned that this might be easier to do in the offseason, and I agree with that. Allen's contract is expiring, but we could easily pull off a sign and trade. Toney is making about 2M next year, so if the deal Ray signs is about 6M/year for 2 years, Grunwald can send the Celts 3M in cash and then the difference would only be 1M. Also, since it's a sign and trade, the Celtics would probably be willing to take just TD (and maybe Bully to fill out the difference). If this trade were to happen before the deadline, the difference would be 8.8M because Allen's making 10M this year while TD is making 1.2M, and we wouldn't have access to the 3M cash because we sent it to the Wiz with Turiaf. Considering the fact that other than Melo/Amar'e/Tyson, only Shump and Earl are making more than TD this year, we would need to bring in a third team to pull off the trade before the deadline.
From the Celtics side, Rondo and TD are a good fit. We all know TD can play well off the ball, plus Rondo is big enough to guard twos, so TD would be able to guard points. Also, the Celtics have a solid backup PG in Avery Bradley, so Toney would never need to play there (and I imagine a recurring wet dream of his is playing a whole game without ever having to run the offense).
As for the Knicks, Ray Allen is an obvious help. He's the most prolific three point shooter in history, and hasn't lost his touch, so he'll do wonders to space the floor. He's a committed defender and good passer, so he won't be a liability in other areas. He's won a championship and is a good veteran presence, so he'll help in the locker room. It's even possible that with both he AND Tyson being committed to defense, Melo and Amare will start giving a full effort there.
Here's what the lineup would look like, assuming we traded TD and Bully and we've resigned Biddy (Earl is unnecessary):
PG: Lin/Baron (Bibby)
C: Tyson/Jeffries/Jorts (Jordan)
It's an 11-man rotation, sure, but Novak would probably be used sparingly, and Jorts may not get a huge amount of minutes either. I think Fields would be much better off playing exclusively at the backup 3, and Allen would allow for that. I like this team a lot.
I don't want this to be looked at as "blow up the team! nothing's working!" by the way. I just think Ray Allen would be a good complimentary piece.