Theory regarding what's happening to Rogue: My guess is that after this transformation when in Otherworld, Rogue's powers will work the opposite way. Rather than draining lifeforce, she will return or imbue it. Essentially making her an "Earth" or "Mother" goddess type figure. That's why she's been doing the Sleeping Beauty/Snow White thing. Scholars have long thought those stories harkened back to pre-Christian myths regarding the rebirth of nature after the long winter. It's also why she was pondering motherhood in the context of the "Make More Mutants" law. To suggest her transformation into a "Mother Nature" type off figure.