The main interest of Black Catle (Great instance, btw) is that you HAVE to cooperate to beat it.
Because like, two people have to stand on separate stone to desactivate a trap while others go through or thing like that. that's why two lvl80 dude, while perfectly able to kick the mob's ass, won't beat this instance if they don't have help.
So I would absolutely love to see a lvl80 version of black catle, but a PVP last-man standing version might be a big mess.