I have this weird idea: How would it have been, had Bethesda created the Elder Scrolls-series as inter-connectable games (such as the Enemy Engaged-series, for example: you can install either "Comanche vs Hokum", or "Apache vs Havoc", and play it on its own, but when installed together, the maps, missions and aircraft of both become available in one bigger game).

You would likely not be able to start with Arena, however, because of the RAM limitation when it came out. Probably not Daggerfall either, as there's a lot of bland empty land that could have been forested or mined or towned/ citied. For me, the series took off during Morrowind, so that's where I would have liked it to start. You installed Morrowind and finished it. And when you install Skyrim or Oblivion, the lands become available, but not the game missions themselves, you need to start in said games to do their main quests. No Dovakiin for Morrowind and no Nerevarine for Oblivion. Or you can play the current game you are playing through to the end, then get a call to go to check out what is wrong in Skyrim and get caught on the border. Or be called to help in Cyrodiil and be framed for whatever and wake up in jail, from where the plot of the game take off.

This is just a wild idea, and I hope TES VI (whatever it will be called) would be considered to be a modular game for Skyrim. Instead of just another TES game, it becomes accessible from whichever province of Tamriel you are currently playing in. And if it is true that they've added the continent of Akavir, that it be accessible from wherever you are in Tamriel.

Elder Scrolls Online basically works like that, with every expansion having its own story and serving as an on-ramp to the larger world. There is a loose central narrative that runs across all the expansions, though. While you can play them in any order and it *usually* works, you'll sometimes meet people you've never seen before who act like they already know you -- or who you've adventured with before that suddenly don't remember you -- if you encounter some of the recurring characters out of order. Overall, though, I really like the idea of a familiar world that keeps getting bigger -- allowing you to explore new lands while being able to return to old places.

In the case of Morrowind, Oblivion, and Skyrim there's also the issue that each of the games have some (sometimes significant) changes to the underlying RPG systems. Take a look at the difference in how skills and attributes are handled between Morrowind and Skyrim, for example. If Bethesda had treated Morrowind as a sort of "world foundation" and added Oblivion and Skyim on to it, we'd still have all of Morrowind's underlying RPG systems into the later games. Whether that would be good or bad is definitely a subject for debate. But the upshot of it would be that if they updated how a mechanic worked in a later game, it would have to retroactively apply back to the previous games too since its all one interconnected uber-game.

This is true for TES 1-5. If you follow the evolution through, you'll see that Bethesda changed the RPG system (and other systems, too) from game to game incrementally, always trying to address (perceived) issues of the earler version in the next game (successfully or not is a matter of opinion).