Runescape diehards will pretty much play it no matter what, and there are plenty of those. I don't think the majority of existing MMORPG players could get past the simple fact that it is Runescape, though, no matter how updated it would be.
No. The thing I liked most about RS is that a lot of stuff took a LONG time to do and it felt good to complete one of those tasks, like 99 mining etc. Too many people don't want that.
I don't think that will happen, and I don't think it should happen. I don't know if the game is free or not, but when I used to play, everyone I knew played it because it was simple in terms of playing it, it was fun, you could be a mage, a fighter, a tank in a moments notice and the way you level up and cut wood and farm stuff is very cool.