Nah, no sequels. Really, the plot itself is by far enough. We don't want some far-stretched plot like Taken 2. On the other hand, Bioshock 2 managed to create a sequel with no direct links to the first game, except for Rapture itself.
However, the world of Dishonored is huge, as we can see on various maps. The Isles are very small in comparison to Pandyssia, and Dunwall is just one city on the south coast of one of them four isles!
There is also some nice background, with a lot we learned of by listening to conversations or reading books. Order of women branching from the Abbey, other cities, the mines in which the pendleton brothers are sent, Daud's background. There is much to do.
It should be known that Arx Fatalis had some nice lore, too, in his time, and a sequel would have been quite possible. They never did one. I guess Bethesda will urge them to do sequel(s) to Dishonored, but it doesn't look like the kind of thing Arkane do.
Corvo is shipwrecked on the continent after someone kidnaps his daughter (with Callista) or something.
The game sooo strongly implies that Emily is actually his daughter, that I don't think they would ever give a clear answer to that... Certainly not by giving him another one
