Imagine this as the opening video for TESO:

4E 205
Archaeological Site
Somewhere in Skyrim

Researcher: Ah... Dragonborn... Thank you for taking my letter seriously enough to come. We are at a critical point in our research, and we found something that we feel only you can help us with. It is an artifact that has inscriptions in the Dragon Tongue. We had members of the College of Winterhold examine it and there is an aura of magic around it, the kind of which suggest it is some sort of repository of information. They feel that only a Dragonborn can open it and learn what knowledge it may impart. I felt it was important enough to request your presence.

Researcher brings the artifact and holds it out to the Dragonborn, who takes it.

FLASH

Darkness... Fade in slowly to show Molag Bal standing before the Dragonborn:

Molag Bal: I knew this day would come. For over a thousand years it has been a certainty. I welcome you to my realm. Two hundred years ago, the last of the Septim emperors sacrificed himself and forever cut off your realm from our direct access. But the artifact your shell holds in its hands back in your realm is a gateway from there to here. But only for your soul which I now claim. You are not dead, and you cannot die. Not where I send you. You go to a reflection of Tamriel as it existed over a thousand years ago, when there was no permanant emperor and where citizens of the Empire did my bidding. When I send you, you will remember this only as a dream and your new life will begin. Why am I doing this? Because I cannot allow you to interfere with my plans for your world. Oblivion cannot open a gateway to your realm. But those who slept are now awakened and they will open a gateway to Oblivion, and what I feigned failure to achieve long ago, I will achieve now. For you will not be able to stand against me as Tiber Septim did. For you are as he was. You will stand for all time in your world, in the vault of ages my followers built so long ago, like a statue. Neither living nor dead... Soul-less. Impotent. No threat to me. Mehrunes Dagon had his season. Sheogorath as well. And soon will be the season of Molag Bal! Depart now into the endless night I have prepared for you.

FLASH

Darkness... Fade in to the interior of a bedroom. First-person-perspective.

Camera rotates down from ceiling and seems to move around with the perspective of one getting out of bed...
Camera approaches a washbason. Sound of water being poured and of hands splashing in it. Hands cover camera as if washing face... Vision blurred as camera turns toward the mirror. The reflection is not clear. Camera zooms in and...

ENTER CHARACTER GENERATION MODE.

EDIT: nevermind. The idea is too much of a stretch though. It's not as profound as you might think it is.

Skyrim is not the "core game" and trying to tie ESO to it this blatantly is in my opinion just plain stupid. The game would gain nothing from being some silly flashback/dream of the dovahkiin.

I meant Core Series.

I used Dragonborn as an example because that is currently the primary role we play in the latest game in the core series.

It makes TESO relevant to the core series and the core series relevant to TESO while giving an explanation as to why the events of TESO do have not impacted the history of the core series world, while keeping with the whole "Molag Bal steals your character's soul" idea.

It was just a hypothetical idea anyway.

Interesting idea. I agree though that it would look like a sad attempt at trying to use the BGS games to prop ESO in a better light. As long as the game feels like a TES game, I think that will be enough of a connection and make many happy.