I suspect many of those animations are the Momentum-less versions of the animations. Momentum is a new mechanic for the powerset, where after your first attack connects, you get Momentum for 5 seconds. While you have Momentum, your attacks animate with faster, alternate, versions of their animations.
This theory comes from the fact that two of the powers require you to have Momentum to use, and I only noticed two attack animations that didn't have that ponderous windup. I don't have Beta installed to personally verify however.
Edit to add: I also recall hearing on the official forums that there may be an animation bug with the fusion hammer, where you strike the ground with the rocket end instead of the flat end. >.>
This theory comes from the fact that two of the powers require you to have Momentum to use, and I only noticed two attack animations that didn't have that ponderous windup. I don't have Beta installed to personally verify however.
Edit to add: I also recall hearing on the official forums that there may be an animation bug with the fusion hammer, where you strike the ground with the rocket end instead of the flat end. >.>