I think it should be quite simple.
Whenever you find an opportunity to improve for both the short and long-term, do it.
If there's a deal out there involving Rondo, Jeff Green, etc that makes sense (preferably for players, not more draft picks) then do it.
If there's a deal out there to pair up an established player with Rondo, do that as well.
But, make a decision! Are you trying to be good for next season or are you looking to go the Sixers route and take a long-term approach? No more 25 win seasons and number 6 picks in the draft.
Either you're in it to win it now, or you're taking the long way home.
Don't try to have a little bit of both.