As the OP of one of those threads, and probably that thread, let me explain.

You may or may not know but the server is not perfectly in sync with the client's display on positioning/facing.

Regen generates more threat-per-hp-healed than a cure, but that's not really an issue. Paladins should be able to out-threat your heals.

The problem is that when I pull, or any paladin, since the toolbox is limited.

I shield lob my first target. This isn't going to hit you, not from regen tics.
I try to race to the pack, get a Circle of Scorn off - this is off the GCD and immediately says to the mobs "hey, attack that guy", a tick of regen will out-hate a tick of Circle of Scorn. Paladins, leveling, won't have CoS.
Immediately after this (within like a second), I flash. There, now I have hate.
I do my single target rotation and flash again, you're safe.

The problem is if a regen tic flies off at just the wrong time during the pull, even if it was 100% overheal, the mobs start heading to you and even though, on my screen, I flashed at the proper spot to avoid this, the server frequently disagrees. The best thing a tank can do at this point is run to the whm, and try to flash there.

If things are waking up and coming for you, that's usually a tank not doing his job, not flashing enough.