What MercuryPenny said pretty much. I mean, we also have YI hacking and SM64 hacking but they're in no way replacing SMW. It's just expanding the amount of games we hack (and with this, we're actually taking 4 games in 1 go).
I'm sure that most people want to hack SMAS badly, but there's just no editor for it at the moment. I'm predict that especially SMB3 hacking will be popular.
. I could post stuff now and then
My Assembly for the SNES
tutorial (it's actually finished now!)