Regardless of sales, I am really stoked for Fable 3.
It will be like your run-of-the-mill Fable game except this time the entire first half of the game is starting a revolution, gaining allies, buying safehouses, and whatnot to overthrow your brother who is a tyrant. The 2nd half of the game puts you in the role of king and you get to decide how to build your kingdom, what to build, where to build, and all the other fascinating political stuff of ruling including war with other nations and factions.
Your character now has a voice, so I think it may be gameover for the cute little "expression" system. Your character can grow angelic wings if you are good enough and I believe Soul Reaver like wings if you are evil. From what I have read, you have complete power over Albion and can punish and reward any Albion citizen you please.
Most interesting, there is no menu system in game. From the interviews, to change clothes you have to go into a dressing room. Furthermore, you can create your own weapon from the ground up and sell it online to other players.
As for other changes, I hope they revamped the spell system. Having only one spell hotkeyed to each level was mighty annoying for those of us who did a pure will user playthrough.
Furthermore, Fable 3 needs a couple of really hard to impossible bosses like RAAM in Gears of War. The end boss fight for Fable 2 was the definition of anti-climatic.
Finally, a tad more complexity to the morality system would be appreciated. Fable 2 had good/evil and pure/corrupt.I would suggest a order/chaos where the more inattentive you are in ruling, the more chaotic your kingdom will be leading to shanty towns and rebellions. Those with more order would have a society that is tightly regimented possibly to the extent of a caste system if too attentive as a ruler, less rebellions, and cleaner cities and towns.