I am not a follower of college basketball, but judging from reports, I got what I was asking for...big men!  Sullinger's back concerned me when he was drafted, but his chances of big minutes during his rookie season is slim anyway, so I am looking at it as he has a year to get healthy and learn the system.  The fact that he was projected to be a top 5 pick before the reports of back trouble makes him a steal if the Boston medical people can work their magic.  
After researching Fab Melo...he looks good too.  Maybe not the quickest learner (maybe a language barrier?), but we have some good teachers in Boston in Doc and KG...and you can't teach size.  
The way talk is sounding, Sullinger can possibly be a star, and Melo can a be good  defensive center in the NBA for a long time. Like someone else said, it takes about three years to develop a center.  At the very least, trade possibilities have vastly improved.  This is their year to learn for the transition to the "Rondo Years".  If they have a smidgen of Perk's work ethic, they should be fine.
In the meantime, (hope my green goggles are not steamed up) if everyone comes back and we can add a free agent or two, the Celts will be in the mix for next year's run.  Go Celtics.