Yeah, Hood is a quality NBA player, Young probably isn't.
I think the idea that Hood would be the second best scorer on the Celts is a dubious one, but I guess we don't know for sure either way.
The Young pick was a swing for the fences that ended up as a strike. Missing Hood (and Capela, and Garry Harris) with that pick is a bummer, but hardly make-or-break for this team.
At least Ainge didn't waste the pick by going for an older zero-IQ project big like Fab Melo.