Again, not asking for balance here. The -RR% existed on the set for years and didn’t hurt anything by its existence before, so what’s the problem with keeping it? 
Ultimately it’s Z’s game and up to him what direction it goes and where it ends up. I’m just a humble 10k hour player who’s happy to play in a way that I enjoy. DDD is not a Crate approved method to play and Z has stated he will not balance around that. No skin off my back to ask for something here or there!
Set was turned into pure Acid.
Thanks. Without Grimtools showing the diff I’m blind. 
it really wasn’t though, the % vit damage is still there, the helm still converts ele to vit, it’s still vit + acid sigils (converts fire & chaos). it’s literally just the acid kalastor addition and the censure mod that’s changed.
Kalastor and Drain Essence are pure Acid, Sigil was already 66% acid and the flat vit on the set bonus was changed to acid. It’s an acid set.
The % vit is there because items have the % damage that is being converted into the actual damage type of the set (Deathmarked has % pierce but the set has a bunch of conversions from pierce to cold). The elemental to vitality doesn’t make any sense for the set anymore, but it doesn’t do any harm to keep because of the skill mod conversions.
I’m more upset with why Sigil lost the 1,5 secs cdr and the 50% energy cost reduction mods.
O.o the fuck? just why?
Let’s get that back! I didn’t notice that change. 
Sigil spam is kind of a cool thing.
Totally understandable. RR was there already, keeping it won’t hurt the balance really or open up some broken builds. All valid concerns.
I think it’s definitety up to Crate to decide the direction of this: i.e. does Crate want sets/items with item mods that don’t make a lot of sense or that don’t contribute to the builds they were meant for. On one hand, keeping this rr won’t hurt nobody, on another hand, it will look a bit out of place once set’s conversions and overall direction will be solidified as pure Acid. (and then I am sure someone will say “hey, what is this vitality rr doing here, can it actually be something useful instead?”)
Yes please. Hell, even after these changes there’s still going to be some single vit -RR% master skill builds that would hugely benefit from Rattosh getting a buff. Also mean less need to shove all the items with vit -RR% procs on a build to make it work even for ones with access to two skills.
And vit melee is still kinda meh, though I’ve been chipping away at the vit Blade Arc face and it’s currently possible to lift it out of meme status. But it’s a lot of work compared to physical/bleed.
Zantai could solve this though by nerfing the Demonslayer a bit 
Which would allow for vit resists on enemies to be reduced. But the set seems to be protected by eldritch powers lawl.
Rattosh is the only tier 3 RR devo. I guess designers think vitality rr is the easiest to obtain in mastery skills and gear procs, so limit it on devotion.
But vitality RR has too many disadvantages:
this might be an another unpopular opinion but I think instead of increasing certain RRs, maybe we should lower mobs’ resists instead, nerfing some RR accordingly?
it will make low RR builds more viable (remind you, Battlemage still exists).
Both can work but overall vit res needs to go down.
I want the RR from rings to finally disappear. For all of them.
Yeah, this. There are some cool rings, Epic and Legendary, that will hardly ever see use in their respective damage type just cause there are RR options taking up their slot. That will become even more limiting with Epic item upgrades, where many of them are likely to be added to the Legendary pool only to join the pile of unused jewelry.