With the changes to self-healing, it won't be; warlocks (particularly those not playing aff) are pretty much the same as other casters. True, we've got Drain Life, but the cost of using that is so high that we should be moving like everyone else. Shame we've not got the tools that most everyone else has to do so.
As said before, what they've done is design warlock to be different, in that we are suposed to absorb damage, not avoid it, but in bfa they've taken away a lot of the ability to absorb and not applied any compensation anywhere else. With zero escapes and immunities, warlock is actually a fragile class in BFA...and this weakness is glaringly obvious in PVP.
In PVE encounters are at least designed around being able to move out of the fire - in PVP you either have to have a ton of survivability or plentiful ways to escape. And warlocks have neither.
Melee classes make an instant dash to any warlock they see, we're a free HK to them.
The question is, is this nerf to self-healing applied globally to all classes? I've always thought that the removal of Life Tap was a reason why all our heals dived.
Other classes do not have that level of self-healing (save, naturally, healers).
The logic of self-healing was two-fold: first, as you say, Lifetap. Second, however, was to make us different from other casters by making us robust rather than fragile. Other casters generally have lots of escapes and immunitties; warlocks don't. We are supposed to soak up the damage, endure it and sustain ourselves through it.
In Legion in PVP warlocks - particularly aff - are heavily dependent on massive self-healing since there is no way to peel off an attacker or rapidly escape/become immune, particularly melee, and our lack of burst means we take much longer to kill them than they take to kill us.
In BFA these disadvantages remain but the compensating advantage of self-heals has been all but removed.
One of the major reasons self-heals removed was dungeons: afflocks became highly desirable in M+ simply because for the most part it rendered it a group of four as far as the healer was concerned and also afflocks could actually self-heal through mechanics designed to force DPS to move.