I could actually see UBI doing something like this. I haven't played AC:V but I am assuming you can use a multitude of different weapons... I suppose they would go with maybe the default however of Axe/War Hatchet and Shield. That is at least a bit different from Warlord and then we would have to wonder if the hidden blade would be a factor at all. I don't know the more I think about it maybe they might add him in for an event or something but as a new hero... just not sure.
I don't know if the current event hero hints at a possible new hero... although I don't see much of a move set from her.