While I love Leon Powe as a Celtic, Sheed is a much better player. The difference IMO is that Sheed will be effective nitely against starter or rotation level bigs. Leon was inconsistent against starter and rotation level guys. Sheed can step in this year and play starter minutes for perk or KG and we dont see much of a letdown. Leon has never been able to say that honestly.
I think Rasheed Wallace will have a bigger positive impact and be more valuable to us than James Posey was overall. He will play enough minutes to keep KG from being overworked and spread the floor for the second unit better than Posey because he is a better shooter. We will win number 18 because of him, provided we stay reasonably healthy. Those were the two biggest factors last year IMO, with Big Baby's improvement cancelling out the PJ Brown factor.