I think it would be nice to see a little mix of both. Nobody likes being held back constantly in a series, it feels boring and like nothing is ever changing. People want something different, and I have a feeling that's what they'll be giving us. We're already getting an entire new graphics style and gameplay, so why stop there? We're going to be seeing Skyloft, which is also new to us. It'd be nice to see a lot of new areas in the game, and we most likely will be. I have a pretty good feeling about this game, and I just hope that I'm right with these thoughts.
It would be cool and nostalgic to see Lake Hylia again, sure, but I don't want to walk a few more steps and see the Lost Woods, then the exact same Death Mountain we saw in another game, and so on. A mix of them would be absolutely perfect, and I would love it. We've seen new areas in every Zelda game, no doubt that we'll be seeing either entirely new areas or a mix of both in Skyward Sword.