I kinda like the idea of AU, if only because I don't see there ever being a threat that could possibly be made more powerful than the current threats in the ongoing series. And with powerhouses that the main cast have become, they could easily take out any threat below an actual God with little issue, I think, so it may feel a bit weird that they would have a new generation take care of some powerful threat instead. Unless the premise for the next generation idea would still hold a similar feeling, like it all could have actually happened. I did an RP with a friend once where we were Genin on a team at the same time all the other teams were formed in the original series. We'd go through our own story while events from the main series such as the Sound Invasion or the Sasuke Retrieval would affect us as background details or references. It died before we could make it to Shippuden, of course, but it was a really fun and fresh concept while it lasted.

F or M as in Female or Male? It doesn't matter to me a whole lot what gender people are, to be honest. I used to be opposed to playing females, but I'm okay with either one at this point. All depends on what ya think would fit the story best. ^.^