Looking back, one could argue that the last three games could have offered more than they did if Bethesda had either simply spent another 6 months of work or released another 1-2 DLCs/expansions.

Consider:

1. Morrowind - it boggles the mind that we saw so little of that province. There was so much more to see.

2. Oblivion - Going SE into Blackwood towards Black Marsh should have been interesting, not unpleasant. I simply felt like I was walking into a boggy forest, not towards an incredibly exotic swampland populated by amazingly ancient trees. Also, we had an opportunity to adventure into south Morrowind to do things we should have done in the previous game. And how about an actual Sutch instead of a ruined tower?

3. Skyrim - Oh my. Roscrea, New Orsinium, Atmora, Western Morrowind, northern Cyrodiil......the mind reels. Even within province: a much more complete Dawnstar, an actual city for Winterhold and Falkreath and Markarth, a Jotunheim somewhere in the Velothi mountains....

I'm sure I've missed many other possibilities. Anyone have any things they wish they'd seen?

The entire concept of Morrowind was pretty much traversing Vvardenfel, so no, I don't really think we missed a lot. If anything its pretty much THE epicenter between the Imperial/Dunmeri conflict within that game due to it being open for settlement comparatively recently. Not much was really missed for the most part, beyond not seeing the rest of the Province. It just wasn't relevant outside Tribunal. Worst thing I can think of that we missed out in Morrowind is flying bug mounts and the Blight spreading as the game progressed (IIRC, that was originally intended to happen). That was about it.

For Oblivion...well, that game is literally "we wasted a good concept and plot" incarnate, so...yeah.

Skyrim is kinda filled with these, namely we the player character inheriting a position of power that none our predecessors ever really got a hold of, namely rebuilding a group like the Blades from the ground up and leading them towards...whatever. Nope, dragon hunters. More glaring then that is representation of Nordic culture at large and sweeping the lifeblood of a civilization under the rug, despite having the perfect opportunity to contrast different human religions within the series from one another. Oh, and the Dragon Cult. It didn't really get a whole lot of exposition in the end