Nathan - I am not sure what you mean by a sub channel, but I assume you mean a dedicated .1 channel like Dolby Digital. The answer is no, it doesn't, but the bass management will still route bass to the sub. I also notice with DPLII, that their seems to be a boost in the bass, probably because all of the channels are sending their bass to the sub.
As an example of the cool stereo surround in DPLII now, my wife and I were watching the world series last night (go DiamondBacks!), and the crowd was coming out of the surrounds in stereo. My wife even said, "Wow, that was cool - someone just started clapping behind me to the right!". It really felt like we were sitting in the stands during the game. When the announcer comes on, it "echoes" through the room just like it would at a stadium! It doesn't sound gimmicky - it sounds very natural, not processed. By the way, I always listen in Music Mode - IMO it sounds so much better than the cinema mode, and a ton better than old DPL. With my 3802, I can adjust all the parameters in music mode that make it sound how I want it, and it still does all of the steering logic correctly, just like it would in cinema mode.
As far as channel bleed - I have no idea how to measure that, but seeing that it is a matrix conversion, there might be some bleed, but I don't know how you would tell. How would you know if that sound was supposed to come from the back right or the back left or both on normal material on TV? Maybe a test tone could tell, but this isn't a discrete signal like Dolby Digital - it is taking a 2 channel signal and matrixing it to 5 channel surround.
Bryan