This is about what I expect. Bass would be great for them next to Dwight. He spreads the floor and is a very hard worker on both ends of the court. I get that they don't want to 'dump' Asik, but all they did was sign him as a FA so it's not like they gave up all kinds of assets to get him - they just adjust the 'signing' to somebody who more fits what they need.
I don't know that Asik would be the next great center in Boston, but he would certainly be the starter and would rebound the ball (so would Humphries, I guess, though). The other guard in the deal can really be any of Brooks, Crawford, or Lee.