Losing Powe is a big deal for this series, but eventually becomes moot in the next series or against Cleveland. We'll lose against Orlando or Cleveland even with Leon. Scal would help by taking some of Mikki's minutes and will help our ability to respond to early foul trouble, but doesn't really make the C's a stonger team.
Bottom line against Chicago (IMO) is that if Gordon or Rose continue to be unstoppable, the remainder of the games will be close and we'll be lucky to advance. The Bulls have been remarkable in their ability to stop any Celtics momentum with 16-18 foot jumpers that find the net. If they have a game or 2 in which the J's don't fall, the C's will take the series.