The key word here is venue, around here heavy bands play the same venues that rock or punk bands play. Every one of those venues have a PA
How incredibly lovely for you. Your situation isn't everyone else's. The norms for genres you play aren't universal, nor are the norms for the places you play necessarily universal.
I play with both doom metal and folk/rock bands. I almost never, ever have PA support in either of those cases. In some cases, we've had to bring a PA.
Consider that in a 1000 seater the PA you'll need to get the vox and drums to compete with that SVT you're cranking is gonna be in the neighbourhood of a 20,000w+ line array rig. At some point you have to play to the room you're in with the PA you have regardless of how "heavy" you are. I've teched a lot of shows with bands like Sevendust and Megadeth that need to be real loud to be convincing but were pro enough not be clipping the PA or killing the room.
Whatever PA you have wouldn't the ultimate goal be to play at a volume that the band likes, the audience likes, that works for the room manager or promoter (and everyone he needs to keep happy) AND that the soundman can work with given the room and the gear he has? Genre doesn't really have much to do with it.
Neither Sevendust nor Megadeth are doom bands.
People going to stoner doom bands expect volumes that are very high even by rock, punk, and metal standards.
The only things we had in the PA during sunday night's gig were vocals, kick drum, and keys. Everything else was blaringly loud with the rigs. We got compliments about how we sounded from lots of people, including a couple of people who do sound engineering, one of which was the soundman himself.
As for vocals balancing, the goal is for the vocals to be audible in this genre, but not louder than everything else. It really isn't about the vocals, they're just one of the instruments.
Ive played on a few very bad PA's in which I have opted to carry the room with my rig, but those are few and far between. Like I said, I may just be lucky to be in the location I am in.
In rehearsal, do you put the bass through the PA? Most bands I know here do not. We've already had to basically mix ourselves.
Sound people who work the kinds of shows we're on know how this genre works, and what to expect, and that it's basically on the band to have sounds that work well together. Bands that have their act together will sound good, bands that don't will not.
At larger venues, like the Oakland Metro, or the Fox, for instance, bands will be put through the PA. They will still have loud stage volume, because the musicians themselves want to be experiencing the same high volume that the audience is.
Look, people, nobody is expecting you to
like what we play, or be interested in doing what we do. You don't see me telling people in classic rock bar cover bands how to do what they do, because it is their craft, and not mine. They probably know what they're doing if they're any good. The same courtesy should apply here, too.