Tsunade's role in the upcoming chapters
I see a lot of discussion about past hokages, but not so much about the one who should matter the most, all things considered.
I, personally, have two ideas:
*Tsunade will play a minor part in the battle against Pain (such as appointing various nin to deal with him), but a major part in the battle against Madara (a much more combative role). Even if Madara for some reason or another isn't after the village itself, I do think he would enjoy getting some revenge at the expense of Hashirama Senju's granddaughter. From what I've gathered in this regard, Tsunade's days may be numbered. In a recent interview with Kishimoto, he stated that "... Sakura has growing up to do, but Rock Lee doesn't", this being in regards to various student-teacher relationships. In the other relationships he discussed, the ones who had growing up to do had lost their teachers. To get a hint like that from the creator himself helps me base this theory all the stronger.
*Tsunade will play minor parts in both of the above fights, but a major one in regards to a future event in Sakura's life. This one is a little harder to elaborate on, as the best bit of evidence I have is, again from Kishimoto, that Sakura has long since been the manifestation of a 'normal' female, and as such, I don't think she'll experience as big a loss as the other main characters have.
That's what I have at the moment. I'm favoring the first, although that's in a "one or none" type setting. I think it's entirely possible that it could be both, with the second preceding the first for the most part.