Just a minor revisiting of one premise, out of the multiple ones, found in the OP: do we really want to recreate the TPF we had "a year ago", or the "TPF we used to have two years ago?" I mean...why do we want to strive for something we used to have? Is it really necessary to replicate the same,exact type of poster/C&C giver ratio this site used to have? Because, a year ago, and two years ago, and five years ago, I recall a LOT of harsh words, hurt feelings, and bossy, passive-aggressive C&C that was basically...bashing.
I recall that, of the "dozen or so" frequent C&C givers that Lew mentioned that we used to have, there were some people who fairly predictably expressed what I would call "prejudice" toward certain techniques, or certain types of photography, and certain types of photographers, and certain types of image hosting sites; a lot of really, well, passive-aggressive put-downs of "Facebook Photographers" and so on.
My feeling about TPF and the "recruitment" that Lew mentioned in his OP is that photography as a business, as a pasttime, as a passion, is slowing down. Camera sales have reallllly slowed wayyyyyy down. I've seen some of the graphs; camera sales, both P&S, and digital SLR, and mirrorless, have dropped by the tens of millions of units per year, consistently, since about 2009. I think the whole photography craze is slowing down, both for new arrivals to the game, AND also, for long-time people who have...just gotten bored of taking pictures. And I think that might by why TPF is changing.