I for one am cool with the roster just where it is to start the season. We have quite a bit of flexibility and more depth even right now then either of the last two years.
The two biggest concerns seem to be back-up PG and back-up SF. I think we are going to see a lot of House-R.Allen-Daniels and House-Daniels-Pierce as second unit combos. I think they will ask Daniels to bring up the ball and initiate the offense but then House will likely defend the opposing PG. I am not sure who exactly is labeled the back-up PG or SF in that scenario but I think it works fine and will give Pierce and Allen plenty of rest. I don't see a need to bring in the best available PG right now if the best is Brevin Knight or J-Will. (I would have supported Marbury a few months ago but not now with the internet fiasco and with Daniels in the mix).
As for T.Allen and Scal, they are tying up about $6M which sucks but every team has some dead salary (and thankfully both are expiring). The thing about these guys is that they do have value to the Celtics as inactive players who practice and provide insurance. They are veterans and don't need to play to develop. They can just hang out for half the season if need be and then step in. I admit these are expensive insurance policies but pretty good ones.
Right now, there is no way to trade either of these guys and get more or even equal value back to the Celtics. If Tony is active and playing (say Giddens, Walker and/or maybe Hudson don’t stick yet and go to D-League), then he may be able to increase his value. At that point, there may be a worthwhile trade for a back-up PG or for some other need due to injury or something that we don't even know about. There will also be reasonable players (in terms of talent) who will be bought out along the way.