Blizzard has been removing their platform commitment of Mac support from their franchises for the last few years starting with Overwatch. There’s always hope they will continue WoW because of the subscriptions but there is a definite trend heading away from the Apple ecosystem.
Rosetta 2 will be fine as long as Blizzard doesn’t drop MacOS entirely in some future MacOS version. Whether M1 or Intel wouldn’t matter at that point.