Dear Bethesda: 10 Things I Want To See In The Elder Scrolls: Online
7. Varied Evironments
Pictured above is the subterranean Dwemer capital of Blackreach, which was my favorite location in the game. A far cry from the chilly woodlands of the surface, Blackreach was dark, damp, and lit with a blue hue by the giant, ancient glowing mushrooms that filled the area with spores. The only thing that stood out down here was a golder orb (meant to mimic the sun?) that hung over the central marketplace of the area. Now, Blackreach is my favorite locale simply because of the darkness and the glow cast on the area via the illuminous fungi, but it's also one of the only departures from "typical Skyrim" that you encounter in the game. Other than Ragged Flagon, Solstheim, Jorrvaskr, and possibly the College of Winterhold, most of Skyrim was the same old thing: ancient Nordic crypts, scattered caves, and Dwemer ruins crawling with Falmer and Dwarven Automations. Not that these places weren't enjoyable, but the scenery got old after a while - the Draugr emerging from a coffin or a Falmer dropping from a perch or a Dwarven Centurion being awoken from its stand were exciting the first few times, but a predictable obstacle after a while. 
"Okay, I got hi- damn it."
Exploring the umpteenth Draugr-infested tomb just to be rewarded with a chest and a possible Word Wall at the end was fun, but repetitive. Again, seeing as how Tamriel is likely to host far more variety than Skyrim alone, it can be assumed that Tamriel in The Elder Scrolls: Online will remain a fresh experience long after you buy it, compared to how Skyrim will give you fits for a week or so before you learn to predict just about everything.
Skyrim is a cold and frosty woodland, with spots of snowy tundra, cold swamp, and mountainous areas in between? Got it. So Hammerfell and Elsweyr will be arid deserts, Black Marsh will be well... a marsh, and Valenwood will be a forest filled with grand trees? Right? It's just a hope that each country in Tamriel, and each province of those countries, will be as unique as possible, with little repetition between them. Unique accents to a certain country, or customs, or architecture, would be a welcome change from the usual order of the day I've adjusted to whilst playing Skyrim. In the coming months, hopefully Bethesda will release some trailers or teasers to further display their new realm, but for now, all I have is conjecture - and hopes that Tamriel will be a thoroughly immersing experience that feels as new and exciting that Skyrim did, when I first bought it home.