And from half of your ideas it seems like you won't be happy until Fable becomes oblivion in which case why not just play oblivion?
I love Oblivion's scale, size and depth....but, as I've previously stated, I love Fable's look, canon, engines and mechanics, too. I will be playing the next Elder Scrolls for sure, but an Albion Sandbox would be awesome, imho.
Fanboys will clearly shout-down any ideas that they feel are un-fable-like, but it's evolve or die. F3 was simply too short, particularly once you become King etc. There's evident laziness, a disjointed story and some nonsensical elements that detract from what could have been an excellent game. The game was clearly released unfinished too, but I solidly blame MS for that.
I'll be waiting to hear about F4's size and scale before I buy it, though, as F3 was disappointingly short. I'll be taking PM with a pinch of salt now, too. I enjoyed F3 on my first runthrough, as I always enjoy Fable games, but LH need to step up and examine their formula, return to RPG, stop moving the game's tech-level and seriously up the next installments size and scale. Just my opinion.