Well the city of Winterhold in Skyrim was suppose to be filling with many Dunmer after what happened to Vvardenfell according to some lore on Skyrim. The Dunmer will likely play a large part in the city atleast which may lead to some tensions between the newly setted dunmer and native Nords.
I think Skyrim is like a treasure trove of lots of good things and opportunities for some nostalgia is one of them. The Dunmer migration brings not just Dunmer from Morrowind, but the culture of the Dunmer of Vvardenfell. Some Volethi influenced architecture, some burial tombs or little things like the lamps and that soft blue, yellow or red glow they gave off
or some craft works [goblets and glass] or Dwenmer objects saved from the destruction... and of course Alcohol.
But that is just the beginning. As Skyrim is practically surrounded by the landmasses of Daggerfall, Oblivion and Morrowind, I'd expect similar effects on the southern and western borders of Skyrim respectively. Of course I think that all of this is the icing on the cake of the purely Skyrim-esque aspects of ES:V Skyrim.