blade dancer is only op in certain situations. If your team is paying attention you can kill them pretty fast. If anything the only change I would make is to get rid of that perk that automatically fills your health bar after every kill, there is nothing more frustrating than nearly killing a blade dancer then having him kill you to completely regen and then practically wipe the team.
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That is somewhat evened out by the fact that if you take ANY damage before it fully recovers, you lose any shield you gained and take all that damage to your health.