Well, if they weren't deep enough or lacked a little on defense the Celtics got deeper in both areas with the signing of one James Posey (one of my least favorite players). Posey will be a big player for the Celtics b/c he can play lock down defense, he another outside shooter to go with Allen/Pierce/House, he will help shore up a great defensive rotation that will include Rondo/Pierce/KG/Perkins, and he brings a very physical aspect to the Celtics (even though that's what I hate about him most).
Well, the one good thing about this is that unless Miami makes a big move, this further weakens the Heat which is a good thing. However, the Celtics who I already picked to be rediculous, are slowly but surely getting players to fill in the holes that were missing after the trade. Those holes included a better bench, more outside shooting, and more defense.
So far they have added Scott Pollard, Eddie House, and James Posey. While you can't say that Pollard or House are going to make huge impacts, I think Posey will be huge for the Celtics.
The Celtics are also still considering signing Ruben Patterson and Dahnty Jones. Either would be a great addition to the Celtics bench.