Ah, how I'd love to have play with cross-breeds... not that I'm into that sort of thing. Ahem.
*runs off and creates a playable Yokudan-Altmer crossbreed with fortified magicka and adrenaline ability in Morrowind*
He didn't randomly change the course of history in Tamriel.
C'mon now.
Not what I meant, I'd just rather see these sort of major events take place ingame rather than in a book, if they take place at all. I understand that the author obviously has guidelines set as to what he can write (ie, don't discover nuclear fission), but we are taking a series who's fanbase lies amongst gamers and handing over some of the biggest historical changes since the first instalment to readers. Though, wouldn't it be interesting if TESV still took place in pre-Umbriel times and followed these changes? Unlikely, but.
Maybe they picked it clean of anything of value. After all, if the An-Xileel wants to become a big empire, they'd need a lot more than tree sap.
Perhaps I'm using too many historical references. When the Ottomans took over Constantinople, the city was so rich, big and fortified that they made it their own capital, after looting it and converting every church into a mosque. I just thought it would be the same with Mournhold. Loot the city, plant hist trees, etc.
I don't see why not (especially seeing as most of these sort of "fantasy universes" such as Elder Scrolls, Discworld and whatever it is Bioware called their universe, are often envisaged to reflect our own universes with big and small differences, you can easily liken the collapse of the Imperial empire to that of the Roman empire, or any other empire of our ages... you could probably liken every fourth era political shift in Tamriel to similar changes in our world, if you had the patience). After all, Argonia still contains traditional Dunmer territory even after the Argonians were defeated in the Arnesian war (one of Dagoth Ur's objectives was to "recover ancient territories stolen by Skyrim and Argonia"), so I don't see any reason that they wouldn't like to take a bit more of Morrowind, if not all of it. I would have to agree that the MoT crash would drastically alter Morrowind's climate, probably making it much more comfortable for Argonian life.
Maybe not to the point of making Mournhold their new capital, but I do think permanent Argonian occupation and expansion in Morrowind is quite likely, if only to build up a resource-gathering and trade empire. Keep in mind Black Marsh has already been proven unsuitable for most typical, useful and valuable crops grown elsewhere in Tamriel, and without the Imperial Empire to mine out all that ebony, diamond and kwama eggs (ah, so delicious), somebody's bound to take control. Perhaps they'll just establish some plantations and basically use Morrowind as a cash-crop?
EDIT: Also, gotta love how something that is, ingame, not much bigger than a decent-sized house and suspended only a few dozen feet above the ground manages to decimate Vvardenfel.