Now I'm going to go ahead and say this is pure speculation, but the vision the devs have for these vamp changes dont really make sense. You say you wanted vamps to move away from being about the "strong passives", yes okay. But do they realize they are just trading people humping vamps for the passives to people now humping them for the 1 or 2 skills they'll actually use....and the passives?? I can literally stay at stage one and get all of the new skills with little drawbacks. I can already see people slapping on blood frenzy at stage 1 and not really doing anything else with class. And tbh that skill shouldn't even be that potent, anything that's gives 600+ weapon and spell damage on a damn toggle just shouldn't be in the game lol. I can see the Ohko bomb builds from a mile away.

And let's talk about the passives.
Stage 4 is ridiculous and should've never had the sprinting invisibility passive. They should've had a teleport/dash ability locked behind stage 4 instead. As it stands now, no one but a few bomb builds and NB will even use the passive.
The 20%ability cost increase should be lessened to 10% while the 40% vamp skill cost decrease should be lowered to 10 -20%. The vamps skills should scale with the actual stages instead of being a flat cost/reward across the board. For example if blood frenzy gave 200+ weapon and spell damage at stage 1, while at stage 4 its boosted to 400 etc. This way you dont get people trying to cheat the system with these type of abilities.

So really I'm feeling like either the majority are going to drop vamps entirely, or peeps will just get it for the 1 or 2 good skills and stay at the lower stages. Because honestly, flirting with death just to put out the same or only slightly higher dps is more a deterrent than a beacon.

I dont know why people had all these hate boners for the current vamp passives in the first place, but they aren't a requirement and never have been. Most of the people I know that do endgame content only have vamps for any guildies that may want a bite.
I don't think removing vamps flexibility (especially for healing and tanking) for niche builds is a good change. Especially if you are gonna make it so that everyone can abuse the skills at full strength while in stage 1.
Either way I'm sure they are going to go through with the pts changes as they are, its gonna be funny watching pvp go to shite while pve vamps disappear after a few weeks.