Jeff posted a great figure on the home page from basketballreference.com that shows the estimated lifetime win shares for a player by their draft position.

This is really what the draft, and particularly this draft, is all about.  Only in the top few spots do you typically select a player who will carry a franchise over his lifetime. 

Once you go past the top spot, the estimated lifetime win shares reduces exponentially.  So much so that picks from 10-15 only have as much as 5-10 more win shares during their career compared to the picks in the late teens and early 20's, where the Celtics are picking.

Based on these data, we should definitely not trade both our picks to move up 5 spots in this draft.  If anything, we should trade down and pick up a future first plus a second.