I checked and I'm still getting the exact same per-tick non-crit from my normal non-Ardor'ed aura that I got since update 7 or so.
34 per tick, on a 20 Cleric, Emp Heal, Sup Potency 7 item, 20% amp item, 10% amp shipbuff, Human improved recovery I and II (so 20%).
DI is very situational. I like it on my main Cleric, but I do a lot of solo'ing. It lets me pull trapped levers in eVoN4 and eWizKing without dying. It lets me stand beside the Titan in that raid and not have to worry about laser or pillar death. It lets me more easily open the path to VoD. It lets me recover from an "oops" moment or a sudden spike of damage.
It's not something I absolutely NEED, however, and my caster's current TR is a Clonk. I will only rarely miss the ability.