Paladin and some other decks may come back, and those decks may keep a check on aggro druid.
Though pally and co may still lose to ramp druid, so ramp druid may still have place… which would also mean aggro druid could still survive.
For the record I’m not too into nerfing mage. I suspect new cards in miniset at the latest would shift things.
Nerfs to other things (or even buffs, though I don’t think devs said buffs are on the way) may also shift the surrounding meta.