I think we all can say that the blade storm series is quite lackluster compared to other epics. Even its ranged and magic counterparts do much better but have the same concept. So what would make the bladestorm series equal with the likes of double tap and relentless, but still making it a unique power that buccaneers can take advantage of? Here is my suggestion.
Blade Storm 1: No change
Blade Storm 2: Make effective range from 1 square (right next to you) to your character's movement range (similar to Dance of Steel and the Poisons). (Note: if you kill another enemy before getting to the designated target, you will go to the target, and the last epic that will trigger will be the second blade storm).
Blade Storm 3: Same as above. Now gives slow and immobilization immunity and removes slows when activated. Still sneak attacks.
Creating a berserker like feel of running across the battlefield, axe in hand, swinging at who knows what next, I think this change can make it less restrictive than before while still being fair. Plus, it has a chance to trigger other epics like flanking, cheap shot, and repel boarders, as well as hold the line, which would in turn trigger vengeance strikes, as well as allowing your companions free reign of movement after your spree is over with. I love buccaneers almost as much as musketeers, but I always felt a bit let down at how controlled their playstyle can be. With these changes, we can truly have fun hitting everything in our path.