I like Exum's game, I think he can be an impact player for a long time in this league as long as he continues to work on his shot.
Still, I think Jabari Parker is #1 on the C's draft board - even over Embiid. That innate ability to score, he's like a hybrid Paul Pierce/Carmelo Anthony but without all of the early questions about his character. I think the C's, contrary to what poster on this board think, are looking for a quick turnaround & not the 4+ year rebuilding tear down. Getting a player that can step in and make an impact right away will be too tantalizing to pass up if given the opportunity.
As far as the Rondo blurb, I agree I don't think he knows whether or not he's staying yet. I'm sure he'd love to stay here and try to win again, but he shouldn't be willing to waste the rest of career if things can't get turned around quickly enough.