I'd love for them to do my idea:
Expand and update the engine used in Oblivion, adding all the latest features seen in Fallout 3 as a massive patch. Also, they should re-do the levelling and experience system, making it balanced and more fun. That, and more RPG-ish, rather than arcade-style.
As an expansion pack (stand-alone, I guess), add one new region of Tamriel, and include the patch in the expansion pack. In the pack, it'd include loads of new quests, enemies, weapons, etc. Sort of a new game, really.
Keep adding expansion packs which include each and every area of Tamriel, and in each region, make a "main quest", similar to the one in Morrowind/Oblivion. Though, the quest would have to be massively less important than in both Morrowind and Oblivion (otherwise, it'd mess up the lore if a super-hero saved Tamriel 9/10 times).
Keep updating the engine so you can keep levelling up, and the enemies stay balanced. It'd be very hard to do, but could be done. Then eventually sell all of the games in a big pack.
But, considering they won't do something like that, I voted "yes", because I never played the older Elder Scrolls apart from Morrowind. I don't quite get how they'd do it, but I guess it'd be cool.