Crowder is basically James Posey 2.0.
He can put up pretty good stats if he's one of your top 2 players (see Posey's half season in Denver and first season in Memphis), but even if he's not one of your top players he'll always be a key contributor, especially to a championship caliber team (like Posey was for '06 Miami and '08 Boston) due to his hustle, defense, effectiveness without the ball, and ability to play multiple positions and play in just about every lineup (1st unit, 2nd unit, small ball, defensive, shooters, etc.).
Unfortunately, what we're seeing now I think pretty much Crowder's ceiling or at least close to it.
If you can get Love with Crowder as the main piece (and not combined with a Brooklyn pick) then this would be probably one of the best examples of buying low, selling high.
And the beauty of it is, if the C's were to trade Crowder, while we'd all miss him if he went to Cleveland (or any contender), his numbers are going to take a huge hit. He probably wont even break double digit points (again like Posey). He'll be a 4th/5th/6th man and average 7-10ppg, 4-5rpg, 1spg. It's not like you'll trade him away and he'll turn into an All-NBA first team player and make you really regret the trade for years to come (like Tractor Traylor for Dirk, Vlade for Kobe, or Polynice for Pippen).
I love Crowder, but you got to sell high if the opportunity arises. This would definitely be selling high. Also can't be scared to break up a .500ish team.