Will this actually do something good for the game’s replayability though? It’s not really rare for games to offer multiple character choices that differ in their plot progression and even gameplay, but whether this truly expands the game’s horizon and makes players inclined to come back to it is a different story.
Unless the two characters are drastically different and offer a completely unique look at the game’s contents, most players will probably just pick the one they like most, finish the game with him/her and be done with it, never giving it a second chance.
However, even that might still be better than the previous game. It will ensure that players of all types and with all expectations are satisfied, instead of just those who approach the game with the idea that it will be a gory action.
That way, those who want a good stealth experience will get just that, and they won’t need to come back to the playthrough with Corvo if they’re not interested in this style of play. Hopefully, the game won’t lock too much of its storyline behind this wall so that everyone will get a chance to find out what happens in the end without having to play through the entire game all over again just for a few extra bits of information.