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?