I wouldn't do it - as Ainge has said, KG and Pierce are more valuable to us then they are to other teams. No other team is going to offer a valuable deal for those guys.
I would actually much rather trade Rondo - even with the injury he still has higher trade value than either Perice or KG, because only contending teams will have an interest in the vets while everybody would be interested in Rondo. Even hurt, they will see him as a guy wh can sit out, and then turn them into contenders next season.
For us both KG and Pierce are on pretty hefty contracts, around $25M combined. Once those two guys finish their careers here we let their contracts run out, and then we have $30M in cap space (Terry will likely retire at the same time) free. If we could get a young stud like Eric Gordon in return for Rondo we have our future scorer, and we can make a run at some All-Star calibre players in two years time. We already have a great collection of future support players (Bradley, Lee, Green, Sullinger) so if we add a guy like Gordon to that group and then add one or two All-Star calibure guys in two years time we are pretty much set.
We really need a player who we can build around for the future, and Rondo (good as he is) isn't that guy. Neither Pierce or KG will get us a potential franchise player, but Rondo could.