QUOTE(gpstr @ Apr 1 2015, 08:15 PM)

There's one and only one thing that I really want to see Beth do with TES - I want to see them revive the spin-off "Elder Scrolls Adventures" series and put Todd in charge of that, then put somebody who actually understands and appreciates roleplaying in charge of the main TES games. (Or, conversely, just complete the transition of the main series games to linear action/adventure and create a new roleplaying spin-off series - either way)
If they don't do that, then there's no point in even speculating about anything else.
I'm assuming, from the way you phrased that, that your preference is for the roleplaying alternative. If you take that to its logical conclusion you should have no questlines at all, perhaps just an objective, such as overthrow of the Thalmor as in Destri's proposal, but without a pre-defined path to get there.
So how could a game do that? Maybe it tracks your successes in the various guild scenarios (mage/Psijic, Thieves, Fighters, Assassins, whatever) by their affect on the stability of the central authority. You could take over forts for the rebel causes, assassinate incumbent officials, steal stuff, take over sources of magical power, or whatever it takes to weaken them. If you want to play a Jack-of-all-trades, they wouldn't all have to be part of a single questline, but you'd have to do joining quests and you'd only get quests suited to your skills, so progress could be slower.
To avoid the potential chaos of the game having to account for the consequences of all your possible actions, you'd reconcile the situation at various levels by having other unseen actors perform the other tasks for the current step. E.g. If your character steals the Staff of Excessive Magical Power, then the High Wizard is assassinated by someone else, and Fort Wurble falls to the rebel armies under another's leadership.
Side quests get you followers, equipment, spells, whatever you need to advance your skills, much as they do now.
That kind of game, though, won't appeal to those who want to become leader/arch-mage/king of everything. But there are probably a lot of folks who just want to be acknowledged as a Hero of the overall campaign, much as happened at the end of the Oblivion MQ. It also has the problem of coming to an overall end, when your side wins, which is why they've always had the separate questlines to give you more to do after the MQ. I'm not sure what fills that gap.