Personally, I think it'd be cool if they just buffed Walking Dead to have an, "Enhances Souleater" effect. The effect being that it pushes Souleater's heal to x10 its normal heal, giving the DRK just a bit over half their health on their own. You know, be thematic, the idea that since they're bottoming out and about to go that they want to snatch up some life essence and their "zombie" state makers their sinister sounding attack more edgy.

And then people might even push for Skill Speed builds in order to get in 2 Souleaters without having to worry about timing GCDs or holding GCDs to heal it all on their own.

But more on topic, Invulns are fine, and I'd hate to see them go.

I mean they could just design fights where even if we use them, we eventually still have to do the mechanic, depending on comp. I remember back in Neo-Exdeath I'd eat the first Thunder IIIx2 with Living Dead. My PLD co-tank would eat Double Attack with Hallowed. We had to share the second Double Attack. We had to mitigate for the Aero IIIs and swap to have them all mitigated as well.

I'd also love more gimmicky tank busters, like ones that apply DOTs or automatically critical hit or cause knockbacks. It'd be really cool if they mixed Allagan Field with a tank buster as well. You eat the tank buster, and if you didn't mitigate it properly/enough, it'd deal raid wiping damage. Make the Allagan Field effect also linger for a bit, so that if the swap wasn't prompt, despite proper mitigation, everybody dies. It'd be glorious.