I think the OP presents the choice as much more all-or-nothing than it really is.
Keeping Rondo past the deadline this year doesn't commit us to anything. We could just as easily trade him before the draft...or in a year. So one question is, how does his trade value now compare to his expected trade value later?
I'd argue that his value is very low now. There are a ton of sellers, which is driving down the price of players everywhere. Look how little Chicago got for Deng. Is Rondo really more valuable than Deng right now? How much?
And, I'd argue that his value will probably rise. Uncertainty about his level of play will go away, and unless he's a shadow of himself he'll be at least a borderline All-Star. And after this draft, you'd expect it to be more of a buyer's market.
On the flip side - what do we "lose" by keeping him? The merits of the draft aside, you are looking at maybe +5 wins with Rondo, which translates to perhaps -20% at a top 6 pick, which itself consists of a bunch of guys who are themselves unknown quantities. So by how much, on the margin, do we really improve our expected draft talent without Rondo?
And again, it's a continuum. Rondo might play the last 40 games of the season. He might only play 20. He could get hurt after 5 - look at Rose. So, in all likelihood we are not hurting our draft slot by so much with him as without him.
And even if you think the draft is where you want all your eggs, the right comparison is this:
1. By how many slots would we move up without Rondo on the team for the rest of the year?
2. By how many slots could we move up by packaging Rondo and our 1st round pick on draft day 2014?
To me #2 seems like the far superior bargaining chip, particularly since we will know much more about the draft quality, and be trading Rondo plus our pick for a certain pick rather than a bunch of lottery tickets.
