Main reason no one cares about neptaris in pvp is that pvp is a ghost town. Rogues have the same issue with daggers, mage with staff. You can run away from the proc. With wars they can run away from proc also but if you have axe ready you might hit someone. Even with Polaris I miss 3 out of 4 times trying to land the proc even with axe. For a laugh try to hit a stunned rogue with polaris. They still dodge 3 out of 4 tries.
Charged attacks can still be dodged so good luck. I don't see either weapon as a viable option long term, if people go back in pvp that is. As is it's irrelevant.