The "out there" ideas are definitely the most appealing. With any TTRPG, it's easy for a gaming group to fall into familiar patterns (Oh no! More orcs!) so concepts like Kazarak are great, since they mix up seemingly incompatible ideas into a playable framework that allows a group to take "the fiction" in entirely new directions.
So any of the ideas you suggest (Yellow Tangle, etc) sound great - for me the value of Plundergrounds is to show what's possible, and encourage DW players and GMs to shake things up a bit and get that Mole Machine rolling!