While mild adjustments to the camera aren't impossible, I believe the chances of a 1st person mode being implemented are slim to none. I don't know about development, but I'll bet my left nut that translating all of the animations to a 1st person perspective will require an unholy amount of work. The only melee game I can think of that does it is TES, and without the intent to bash it, it doesn't have the complexity of animations TW3 has.
Pardon the language. Been spending a good many hours with Zoltan and Field Marshal Duda in the books lately.
I agree, there has to be a lot of adjustments before First Person is possible. Right now, I think I would be sick if I was playing First Person with all the pirouettes and turns and dashes.
And yeah Skyrim has a few melee animations and no really complicated moves for the character, so I doubt want to see TW3 combat simplified just for the first person view.