The matchup issues scare the hell out of me. I don't know Perk's specific numbers matched up against Shaq, but at least he's got the bulk to D him up - but who else? Whether Powe's improved his D or not, he's giving up what, about a Rajon Rondo's worth of body mass matched up against Shaq. BBD's got the mass and the low center of gravity, but if Shaq's got some of his little hook shots going, what the hell is BBD going to be able to do about it? You can't put KG on him for any length of time.
If I'm Cleveland, I trade Wally for Shaq in an instant, he's just exactly the kind of player our frontcourt isn't well-equiped to handle.