Remathilis
Legend
Which is exactly what I'm trying to avoid.Yep, so like I thought, you get your divine order choice at 1st level, and then at 3rd level you get the subclass’s original 1st level feature (along with its 2nd and 3rd level features). This will mean if you plan to take a subclass that originally granted weapon or armor proficiencies, you’re strongly incentivized to take Thaumaturge for your divine order choice.
I've been mulling it over for the past few days, and I've decided that some of those features can easily be removed without crushing the power of the domain. So to go back to my list.
Arcana: All the cleric domain grants is those two cantrips. Its probably fine regardless of which Order choice.
Death: Reaper is unique enough that it is fine to leave for now. Just get rid of the martial weapons.
Forge: Losing the proficiencies won't hurt this subclass.
Grave: Circle of Mortality can live without Spare the Dying, though I think casting it as a bonus action is nice. I'd probably leave it but remove the range increase.
Knowledge: Probably fine as it is, if a little boring.
Nature: Allowing the cleric to pick druid cantrips and an extra skill won't break anything.
Order: Losing the proficiencies won't hurt this subclass.
Peace: Losing the proficiencies won't hurt this subclass.
Tempest Losing the proficiencies won't hurt this subclass.
Twilight: Losing the proficiencies won't hurt this subclass.