Not much concrete information has been released covering combat and the different fighting styles. However since I have never been shy about adding my two cents to the conversation I'll just put forth what I think...
Since the devs are working hard on the animations to go with different styles, the odds are slim that they will introduce a completely new style for just one weapon. Perhaps over time much after the launch when they have more time they may introduce another style if they think it is needed. Sort of that we will be stuck with that they provide at launch.
The different styles will be broken down into individual moves, such as a 'thrust and parry' or 'shield bash and slice.' Each style will have distinctive moves unto itself, so other styles will not have that same exact move (though some may be similar). It will be up to the individual players to find trainers of a particular style and learn the various moves with in it. When proficient a player may choose to train the advance levels of that style or moved on to another style to learn.
During actual combat a player will be able to pick and choose from the different moves that they have learned from the different styles. It doesn't have to be all from one style, pick what works. Now depending on your weapon of choice, some moves will work better than others. It will be up to the player, during training, sparring, or real combat, to find the moves that work with their weapon of choice. So no matter if you use a proven weapon or a newly discovered one, it is up to the players to find the style and moves that work with it.
The above is just my opinion or conjecture and nothing factual is implied. When more information becomes available then we can start to more fully understand how combat is actually going to work.
