There are a lot of design problems with Living Dead.
1. There's no gauge that indicates how much healing is still required to remove the effect. You're almost certainly going to overheal it without benediction.
2. It's not intuitive. There is no obvious indication to your team outside of a single buff icon that the effect is active and still needs to be addressed. A new healer has no idea what to do with it unless they mouse over it, read the (incorrect) tooltip instructions, and cleanse the effect.
3. The tooltip is still wrong.
4. Benediction syncs up poorly with it. Benediction is a 180s recast, and Living Dead is 300s. If you use Benediction on the first Living Dead use and want to have it up for the second use of it, you waste a recast.
5. You would think that the cooldown with the greatest penalties would have the shortest recast. That isn't the case.
I think the core problem here is that the devs are trying to make all of these invulns "unique" relative to Hallowed. But here's the underlying problem. Invulns are broken, and they trivialise tankbusters when you have four uses per fight between your two tanks. Let's get rid of all of them, and actually learn how to ration cooldowns again. Then you'll have at least one way to differentiate tanks who needed the crutch and those who don't.