In vanilla and TBC warlock pets only really are for pvp and questing due to how strong demonic sacrifice is, even if pets had avoidance and didn’t get 1 shot.
What if a warlock specced into demonic sacrifice could use a rune that lets them semi-permanently enslave a demon for x-period of time? You could keep them in a bottle/pokeball/whatever, and its good for a couple hours.
Or you could make it so you can have x-amount of ensalved demons before a raid that can be popped out as a cd.
Of course the stats of open world enslaved demons should be adjusted so they are not too ridiculous.
This would help solve the issue of warlocks not using their pets despite being explicitly a pet class, without having to mess with demonic sacrifice.