Maybe a HF-esque expansion where you could expand your homestead into a small village or fort or something. Maybe get the option to adopt older kids, around 18, or so, that you could train and have as a follower.
It will have however many they think they can make money off of. I expect at least 4 real dlcs personally so that means I expect two more. As for the small things that could vary. Oblivion had the horse armor, vile lair, thieves den, the orrery, wizard's tower, spell tomes, and fighter's stronghold.
I would expect that things like thieves den, wizard's tower, and fighter's stronghold will not be in Skyrim though since Hearthfire sort of added all of those in one dlc if you design your houses accordingly.
I hope it gets more, I know the team is currently busy with fallout 4.hopefully they find time.
I might be wrong (i usually am) but i think the ES and Fallout dev teams are separate.
I certainly would like as many as possible. Someone on another post made, what i thought was a comment about this. I can't find it but basically they said that as Skyrim is Bethesdas biggest money maker to date, they'll make as many as they can.
As for specific add-on's, i would like to see (like a good few of you) business owning, a bank, turning your homesteads into small villages, Stormcloaks and Empire unifying and kicking the Thalmor out of Skyrim (thought i suspect this is unlikely).
However, if none of that happens, i would like them to patch it so owning a homestead isn't so ******* frustrating. Every time you go back, your house is getting attacked by something while your house carl doesn't come out because, i don't know, she's afraid or she's deaf.
Even if it's only a quest to raid a nearby bandit camp to stop them from attacking your house for an in game month would make me much happier.