I have heard few people complain about Cyrodiil for that reason. The reason I usually here is "It's boring and Morrowind has a much better environment".
There are beautiful regions in Cyrodiil that aren't covered in snow. Most of Skyrim will be snow. It just makes sense. If it isn't snow, then it will be forest and hills. That sounds like Cyrodiil to me, minus the swampland in the south
Skyrim is also war torn. Cyrodiil just had forts that aged over time. A war torn province in such a harsh land is appealing.
Edit: To answer the other question, Shivering Isles were unique because it reminded players so heavily of morrwind. It was just an alien world. Could they handle other provinces? Sure. Here's a list of em:
Black Marsh: Unless you are argonian, only the outer areas are explorable. And even then it's risking it.
Elswyr: Desert And jungles. But bethesda could be lazy as I explained earlier.
Valenwood: Supposedly magic infused area with walking trees and cannibalism. But again laziness could turn it into just a giant bland forest.
Hammerfell: It would be interesting just for the political war with the orcs. I don't know too much about that place. Antibody could probably provide more.
Summerset Isles: Look at my other post.
Morrowind: It's basically run over with argonians now. We'd get the mainlands, except with argonians and no/very little dunmer.