@Oddthinking glad to hear you came up with a similar system. :) Especially happy to hear that recursive proposition reasoning also came to you. Probably hard to deliver the right kind of UX for it (and imo one of the biggest problems with Arguman), but will definitely look into it.
Fallacy flagging is also on the list, though Arguman made overflagging too easy, just like you said. With SE and Wiki I have two systems that I can learn from, penalty/reward wise. A different route I considered was having a quiz for people to show that they are able to identify sound arguments (would be with ima…