I think if we could improve our ability to easily & precisely communicate arguments, that would be huge for humanity's ability to deal with problems. I'm building a tool[1] that I'm hoping can help with this, maybe be a successor (in some ways) to something like Kialo.
It's critically missing suggestions/approvals[2], and perhaps a simpler interface[3], but I think that, for arguments about problems/solutions, the idea of grounding arguments within a cause/effect diagram is really powerful both for getting on the same page and for making concrete progress towards improving a situation (rather than arguing for argument's sake).
I'd be happy to get your thoughts on it if you have any (I'll be making a HN post about it sometime soon^TM).