What are we supporting here?
In my opinion we don’t need ANOTHER governance UI. We need features to be added to existing ones.
I think you should make a live prototype / MVP before going to the treasury for big spender funds, but even better to work with existing teams and integrate these ideas there.
EDIT:
I think another approach for an MVP would be to take the existing comments on Polkassembly, and manually organize the comments into your structure to show an example of what a controversial proposal might look like with this kind of tooling.
I suspect the best way for your tool to exist would be as an alternative view to the chat in Subsquare / Polkassembly, which could be activated by the user.