With all the all the opinions and bru-ha-ha over the years in regards to TES big three(thus far), being Morrowind, Oblivion, and Skyrim...and now the parent company making an online Tamriel: I would like to suggest (I play on a 360 by the way) to Bethesda to start a fresh, new look on Tamriel as an interconnected disc set. I would gladly give up all my memory space to play all the provinces, at once, given that they have some consistency; that is to say, have the story-line content genious of Morrowind, the charecter development of Oblivion, and the environmentals of Skyrim. Each province on one disc.
What I can't stress enough to Bethesda, is that a good hunk of their fan base is getting sick and tired of the "Sell it now, fix it later" business approach to all their RPGs....Take your time, and get it right the first time (measure twice, cut once). It's better to have a long range game availability date, than a rushed, under tested, piece of midiocrity. You can be better than this!!
In conclusion, I really do like Bethesdas RPGs; even though, I have at times, ripped 'em a new one every so often, it's just that I think they can do better. I say this as a player, and as a person with a vested interest. Anyway, the Tamriel disc set would be nice....food for thought.

TESO. The former can just be made with mods.

The problem with a game spanning all of Tamriel isn't disk size, it's manpower. It's not possible to make a game with all of Tamriel to the same scale and detail as Skyrim. TESO focuses on select regions, and is a whole lot less detailed (both by necessity and by virtue of its genre)