This thread isn't necessarily about the next game, but about a game - either standalone or part of the next one - where we would get to go back in time. It could be part of a main or side quest in a standalone game, or simply a game set in an earlier period, or perhaps a game set in multiple periods where time travel is the essential part of the game.
With that in mind - where would you want to go?
For me:
1. Visit a dwemer city anywhere in tamriel before the disappearance of the dwemer.
2. See Skyrim under the rule of the dragons and their priests. Maybe focus on Bromunjaar.
3. Have a look at Skyrim before the Snow Elves lost control. I'd be particularly curious to see the Whiterun area before the city was there and there was only the Skyforge, standing alone, shunned by the elves.
4. Cyrodiil just as the first Altmer expeditions were exploring the region.
5. Saarthal in Skyrim when it was still a living city.
6. Cyrodiil when the Ayleids were at their height of power.
7. Morrowind just as the Chimer were arriving.
8. Early Hammerfell, before the dwemer disappeared and the Ra Gada arrived.
9. The original Atmora.
10. The original Yokuda.
11. Summerset BEFORE the arrival of the Altmer (that would be awfully strange.)
12. Summerset just before the Chimer and Orsimer schisms, including Artaeum.
13. Blackreach while the War of the Crag was in full swing.
Curious to see what other folks come up with.