It would definitely be awesome, having a whole world to explore, not just a portion of a continent. However, I think it would require working out
a lot of things, and I fear it wouldn't be anything close to detailed. As it is, I already found Oblivion to be much more shallow than Morrowind. For me, it only gave a sneak peak of what the world COULD be and left it at that. Plus I would also fear the system requirements for such a large world.
I myself also cross my fingers to see a few features in TESV. Like better voice acting, or none at all. No voices would mean longer dialogues, better explained quests. Also, MORE CHOICES for what you can/cannot or what you are required/requested to do. For instance, how about you could reject some quests or tell some NPCs off. I hated that for some quests, the only available answer was "Sure!", not unlike the Adoring Fan's attitude...
Some other joinable factions would be nice. I might the only one when I think that the three main guilds (Fighters, Thieves and Mages) are getting a bit old. How about necromancy? Or whatever new exotic group that fits the new region of TESV.
I would also like to see a different start. Being freshly released from jail is not enough for me anymore -- it still implies a past life, experience, attitude... It would be nice if the player could choose a background and history, perhaps follow the PC through their childhood then teen years, with choices to determine how the character could/would turn out. But I'd be happy with a simple test/quiz that does the same thing, with the ability to change everything before you step into the "real world" (seriously, that feature is awesome).
Lastly, I wouldn't complain if we had a bit more insight into the Dwemer and Ayleid cultures, specifically their languages. I realise that Bethesda is not Tolkien, but the random scrawlings that they threw at us in Morrowind's Dwemer books were just ridiculous. The text in the Bible of the Deep Ones (found in Hackdirt's Chapel) is only a tad better; but I have high hopes regarding the Ayleid language. I have just finished the Mages Guild quest at Vahtacen, and from the brief look at the Ayleid reference book, I think it actually looked consistent. [/language geek]
I have a lot more preferences, but all in all, I would be happy to see TESV out in a year or two. Also, first post, pleased to meet you all!