Erm, you may forget that Arena and Daggerfall were predominantly "pseudo-medieval" as well. Granted this was due to the limited graphical engines and less fleshed out culture, but the point still stands. If anything, Morrowind was the
exception for the Tamrielic provinces. Do not expect to see giant mushrooms or hollowed out moons in many of the other provinces, as, in all honesty, most of Tamriel
is pretty generic, at least compared to Morrowind.
But that's not a bad thing. Oblivion's flaw was in its lack of variety, not its general environment. A generic European setting would be fine if it had as much diversity in climates and architecture as Morrowind had. And if anything, Skyrim is probably the Earth-like province with the most potential to be unique - hot springs, massive chasms, hollowed out glaciers, et cetera. I'd say the only other human province that could prove to be fairly diverse would be Hammerfell, http://www.imperial-library.info/maps/map_hf_names.jpg. Desert? Savannah? Jungle? Not bad.
Back on topic, the Nords don't have to be solely influenced by Scandinavia. Bretons seem to be the equivalent of the Celts, but maybe Bethesda could draw inspiration from the Visigothic/Germanic societies as well.