The Celtics are in the drivers seat.
If they don't get Oden, they should try to get a big like Gasol or KG.
If they get Oden, then they can use this package to get either a top vet PG (Kidd) or a SG/SF that can defend and hit the 3.
The biggest key though might be, do not bring back any large bad contracts.
I've said it before, but I'll say it again. I truely believe that KG will either opt out this summer or ask for a trade. I think McHale will finally stepdown/be fired, and Hoiberg will take over the Titanic. There is just no hope there for KG. All their salary is locked up in Hudson, Hassell, Jaric, James, and Blount. All overpaid players who have long term contracts.
I heard Rick Bucher one ESPNews yesterday, and he said something about Al Jefferson and KG. I didn't catch it all, but I think that is a trade that they will revisit this summer. I could see something like KG for Ratliff, Perkins, Telfair, and Al. I think in time Al could be a more interior oriented KG with a cheaper contract for slightly less production, but I would probably pull the trigger on that.
I don't know of a package they could get that would be much better, except maybe the Bulls or Lakers. The Bulls would need to extend some people to make the salaries match, and LA would need to send Kwame, Odom, Farmar, and picks. Not quite as appealing I think.
You are right in saying the key is to not just trade Ratliff for large bad contracts. I hope Ainge doesn't just pull the trigger to appease PP. Guys like Marbury, Hughs, K-mart, Walker, Kirilenko, and Bibby all fit the bill of guys who are good but don't live up to their contracts. Even Kidd and Ray Allen to some degree are like this, although they are obviously in a different league compared to those other players.