I used facebook when it came out because it was a novelty (I'd say revolution but that's probably a too strong word for it) and everyone was curious about it, but I honestly never saw it as a platform to facilitate discourse, to me it always looked like a showcase box pushing on the self-centered nature of most human beings.

Reddit was the perfect discussion platform to me and I loved it to pieces, I agree when you say it holds the largest exchange of ideas, someone compared it to the Library of Alexandria, it's fitting IMO, both in the amount of knowledge it contains and the end it's meeting unfortunately.*

Disengaging from it can indeed be a conflict, easy on one side because I believe most people don't tolerate being treated like s*hit as they did - especially considering that reddit without users is worth nothing - a bit difficult from the other side because it's objectively difficult to recreate the amount of useful content it has, but I believe we're on the right track here.

it’s Reddit as a platform for discourse I’m on my soapbox about

You made me chuckle :D In a good way tho, I'm on about the same more or less :D

Edit: *to clarify what I mean: reddit as a platform won't burn at all, but the quality content will, content creators and power users are always a minority on every platform but they're also the first ones to leave when things go down the drain (Digg is repeating itself).