I'd like to see High Rock and Hammerfell aswell. They're both very different provinces and they both have really cool lore. You have to keep in mind that Skyrim attracted a lot of people to the series (myself included), and they would be taking a huge sales risk if they planted their next game in some place like Black Marsh, which is only inhabitated by walking lizards. Even an Elf province is taking a bit of a risk. I think High Rock and hammerfell add great contrast, could keep the game appealing to new comers and be awesome to play.
A shame this game likely won't come about for some years... There was a five year gap between Oblivion and Skyrim.
Plenty of time to think of ideas, though. The TES fan in me would like to see Black Marsh, but in all likelyhood that probably won't happen.
I think a combination of provinces would be cool, kind of like what they did in Daggerfall. Which ones, I don't really care, so long as we haven't seen them before.
I totally agree with you. But even if the game sets place in one of the Elf or Beast races provinces, i expect dlc's that could take us back to the place that we once "belonged", such as Solstheim in the dragonborn dlc. I hope this becomes Bethesda's practice for next games