Ehhh, idk. They can make a PvE that’s not necessarily horde mode but is played more like normal matches just with bot enemies. I guess like the vs AI mode, but obviously more challenging and more AI bots.
They could also expand on modes like Junk’s or archives or provide more modes of the same sort.
There’s lots of pirate themed skins, for example, why not a whimsical pirate mode, where you’re on a pirate ship and have to face down waves of skeleomnics. Or if boats are too complex to animate, make it a deserted island where we protect the treasure. This would even work as a PvP mode where it could be like a cross between CTF and payload, where one team tries to protect the gold and get it to its hiding place while the other team tries to sabotage them and take gold from the chest.
Maybe not as silly as that sounds, but the point is, it doesn’t always have to be lore specific, they can deviate from the serious stories and create something totally wacky while giving the lore team a breather and giving us something more to do.