I'd hope oceans. That shouldn't require a total biome overhaul like the Mistlands, just new ships and sea monsters.

I would guess Oceans next as it was on the original roadmap after H&H IIRCC,

Then probably Far North, followed by Ashlands.

As for an ETA, given IG's current release record the next big content update will be mid to late 2023 at the earliest.

I hope they do the combat overhaul update before they add new more new biomes. It's frustrating that half the challenge from combat is the terrible weapon hitboxes. Adding stronger and more challenging enemies is fine if they also made the fighting less frustrating. If the next update is focused on the oceans biome as per the original roadmap they should definitely fix the combat first. I'd like to be able to aim my melee attacks at some giant squid's tentacles rather than help it smash my boat into driftwood

Considering the new items we get in mistlands it would make more sense that the next major update could be Ashlands (further upgrades + magic), plus it already has some minor content in it (surtlings, flametal). Though i would like if we get something for the Ocean before this.

Can't really see the far biomes coming before updates to oceans.

The Devs will probably not start on the next major content til after the holidays, but my guess is it will be either Ashlands or Saga Worthy Seas.

Could be deep north too, that's pretty much an empty wasteland atm but could easily be populated with frost giants or somesuch!