This has been my experience with him also.  I played him most of the day today.  I had lucked up and got an Affinity Booster at login.  I decided to use that to forma my Ash Prime.  Went to Akkad a few times to both rank back up and see how effective I could be with Bladestorm in a group.  I would just start marking mode and keep it active.  Targets were being marked as I played using melee and I would get the energy back when they died.  Because of this I was able to activate Bladestorm at anyt