New Mythic Dungeon Difficulty

Unless I’m gravely mistaken, and I don’t believe I am.

Heroic dungeons item level will go all the way up to 489 by the time you’re getting something from the vault.

Assuming you decide to not run any M+ until that point you’d have more than enough gear to not die.

With M0 not having any affixes or timers, that’s more than enough of a stepping ground.