Can I ever comment on something without someone not understanding what I said. I said that volcanic areas typically have lots of islands. I never said that's the only way you can have islands. I was commenting on your assumption that islands must be along a body of water when in reality, that's not truth. Also, there were several islands in Oblivion, the imperial city, the mages guild island, the island where you have to do the Hunters run and so on. There were dozens of more non-memorable islands in Morrowind than in Oblivion. The fact is that Oblivion had some islands. Cyrodiil doesn't need to be dotted with islands to be real or interesting and neither does Skyrim. Some islands are probably going to show up but it is not going to be the same as Morrowind because once again, Morrowind was a volcanic island.
I believe its your tone, people probably get half-way into your paragraph and decide anything you got to say isn't really worth reading.
Anyways, the OP wasn't saying anything about Skyrim NEEDING to have islands, especially not for realism or anything else like that, they just commented that they'd like to have that feeling of finding a little memorable island with a house or something on it.
Second, as you pointed out, there are lots of other ways for islands to form, so why even keep bringing up volcanic activity? Yes, we get that it makes sense for Morrowind to have islands, but that doesn't mean Cyrodiil or Skyrim wouldn't have islands.
Finally, volcanic activity. Skyrim has it, as shown by the map and mentioned by Todd, there is a volcanic tundra. Also as you said yourself, glaciers can help form islands, as well as be islands themselves. Seems like there are lots of good reasons for Skyrim to have islands. The OP wasn't trying to suggest it would be more realistic, just that he wished for that feeling, so really what is your point?