The converse, though, is what has me pondering. Since I am head over heels in love with Lirianne and a big fan of gunslingers, I want to be able to play Lirianne in RotRL - not to mention whatever comes out in Feb 2015 - but I'm worried about how feasible she will be without guns in the weapon decks. How hard or easy will it be to bring those elements into other AP decks?
All I've got is hopes and speculation to share...
My greatest hope is that these games are almost completely compatible with each other. I know that the backs of the cards from the current set do not have their AP identified on them, and I hope that doesn't change... but even if it does, I expect that when appropriately sleeved, you will only be able to tell the difference between—for example—a RotR Blessing of the Gods and a S&S Blessing of the Gods because it will likely have different card art including a different AP banner at the top.
Because of that, I speculate that you could draw Lirianne into RotR, including the guns she will inevitably have access to. So another thing I'm hoping for is that Mike Selinker's team at Lone Shark Games works to balance the new characters for play in RotR. And I know that's a tough balancing act, too, because that means they have to be balanced for both PACG Adventure Paths, and what tips the scales slightly more toward balanced for one AP could easily put the other one completely out of balance.