agree with all the moves being from previous games. The game is only 10% done, there's only a handful of new animations anyway. what the trailer shows are new mechanics (the stepping distance, the new blue and red flashes, ultras, finishing moves..etc) and game pace (faster than SC4). That's pretty much the point of the trailer, it's a sneak peak at how the gameplay.
disagree at Sieg and Nightmare being comparable, they play very very differently and they don't share any moves in SC4. Sieg being very stance dependence, lots of moves but not mobile and Nightmare being very mobile, high risk/reward game, limited move lists. They are different characters story wise. SC3 is where Nightmare ceased to be Sieg with a completely new game style.
and the new Nightmare in this game might not even use the zweihander style anymore since the new souledge takes the shortsword form now.