I'll fire a vague guess at what the next mini-campaign is gonna be. Looking at Subaquatic Menace, the devs have used one of the besy previous MCs (Rising Tides) as a comeback. This time, I think there'll be a Shadowmoon comeback (possibly with a Werewolf hero, Skeleton barracks - there are many possibilities). There are just thoughts, though.
I hope they release the next update soon!