Here's a point that I'm really convinced in: To get a guy like Granger, we would need to trade away at least 2 really good young players, let's say our pick and Ed Davis. Granger will be 30 years of age by next season, so we would need to really be in a big win NOW mode. That means getting to our ceiling by 2013. I don't think that's the plan BC and DC hold.
By not doing such a trade and by trading for Emeka and Mo, you have 6 really good players with a lot of potential that are 25 or younger (DeMar, JJ, Ed, Marshall, Bayless, Valanciunas) surrounded by a big bunch of really good young veterans (Bargnani, Calderon, Emeka, Mo, Kleiza, Gray).
Between both scenarios, I'd take the last one anyday of the week. Much safer and much smart, at least IMO, if we want to be competitive long term.