@VetteC5RX
So I have just tested this in Arcade. Everything I said is still valid, however one thing which I wasn't aware yet was that if one remained blocking Frenzy he could block all 3 hits. It wasn't like that in the past. It still does break the block, but the time it takes between hits is too long to fit into the broken block time window. Good to know.
You're probably getting the "breaking block" thing wrong. There's a difference between breaking block and bypassing block. I know people usually use one in the place of the other, but breaking block is actually making the enemy become vulnerable to damage while his block is broken. When a damaging move does that, it usually applies damage before breaking block, which means that that hit will be blocked, but the block will be broken afterwards. Bypassing block OTOH is when you ignore a block, like Yoda's Dash Attack (or in the past Grievous's spider move, Kylo's Pull, or Rey's Dash Strike). Anakin's Passionate Strike does both Break and Bypassing Block if I'm not mistaken.
So my impressions are either taken from a massive mismovement of enemies when affected by Frenzy, or the help of teammates in hitting the same enemy during the broken block windows.
However I still think this is ok and balanced for HvV. It's still a very powerful ability which helps even when the enemy isn't taking the hits.
To finish this just mind that even if his skill doesn't deal much more damage then his swing (actually it does the exact same), it's still a whopping 125, which can land 0 to 3 times. According to my impressions, if it usually hits once, and sometimes twice, its average damage is something above 125. Vader's choke does around that damage, and also Yoda's Dash Attack, Rey's Dash Strike, Grievous spider move, Dooku's lightning if it hits only one target, Palpatine's Chain Lightning, Phasma's First Staff Hit. So it's ok, as besides those most skills actually do lower damage like Luke's Push, Repulse, and Rush, Yoda's empty Unleash, Maul's Choke Hold, Spin Attack, and Throw if it hits once, Anakin's Pull and Heroic Might, Kylo's Pull, Grievous's unrelenting advance if it hits once and Iden's Stun Droid.
Most high damage abilities are actually from Blaster Heroes like Iden's and Leias secondary fire, Han's Detonite and Shoulder Charge, Chewie's Slam, Lando's Sharpshot, Phasma's second and third staff strikes, Boba's rockets and Bossk's Arsenal. Obi's Push, Ani's Retribution and Passionate Strike, Vader's Throw, and Dooku's Duelist are exceptions.
And if you manage to hit Twice, you're dealing more damage then most abilities (250 damage). Only Han's detonite does that if it detonates really near an enemy, or Phasma's third Staff Strike which deals actually more, or Iden's Zoomed-In Pulse Rifle Headshot from a good range which is the most damaging ability of any Hero/Villain in the game.
Hitting 3 times, which I know it's very rare, actually puts it above the most damaging ability there is (not counting those abilities which may deal loads of damage if all hits are registered, but which doesn't happen ever like Bossk's Dioxis, or Grievous's Unrelenting Advance, all 3 hits of Phasma's Staff Strikes and so on).
BTW, I never said abilities wouldn't cancel his Frenzy. I said heroes engaged in a Frenzy by Kylo hardly ever get to properly use a skill which gets them free, as these skills usually are so slow or require such precise timing that the Frenzy usually hits before the ability works and cancels its effect. One notorious example that usually does get out frequently is Luke, as his Push is fast enough to be used during the time window between Frenzy hits. But then hitting him in the back usually prevents this.
SO in my experience it's much more then 15%. Hitting at least once is something much more then 50% to me, and as it deals 125 dmg and has all these other benefits I listed, I think it's a great skill. Its 40% damage reduction to allow you to leave it with dignity if someone disrupts you is also great and makes the skill a very balanced one IMO.