Portland: Reduces logjam at center while filling their biggest need (a shooter).
Celtics: Add a starting big who's accustomed to their team while dealing from their abundance of wings. Upside off gaining a starting center who can be extended if he can stay healthy.
Notes:
I believe this would hard cap the Celtics
Cissoko should fill a similar role to Walsh
This trade was meant more for fun to see what it would take to get Rob back