i get what you are coming from (and hope that it does happen) but i dont think rondo is a strong enough draw to attract free agents to boston. cap space alone isnt a guarantee of landing a FA. we saw last year that there were some teams with cap space that struck out in free agency.
now, say the c's somehow pull off a trade for a chris paul for example (maybe a rondo/green/filler for cp3/filler)and still have enough cap space, that obviously changes things. but rondo/pierce to me at least isnt that great of a draw. unless rondo comes back next year and can shoot the j/ft's consistently and become less of a offensive liability on the floor. but i doubt that.
I understand it's not a guarantee, and I am not saying this is necessarily the plan. But I can't see any other scenario in which we're up for anything but sustained mediocrity through the prime of our best player.
I am not sure why you'd think we need to land Paul. Rondo has received decent exposure over the last several years, and has done enough, I think, to be considered a top PG. His jumper, I think, is decent enough at this point not to be a an absolute liability.
The appeal of playing with someone like Rondo if you're a big man is that he's a guy who can get you a ball in your spots. To me at least, Paul lost a lot of his luster with a decidedly mediocre campaign this year. I know he's been injured and all, but he went from averaging 22 points in 2009 to 16 points this season.