I can see that the idea seemed fun to Jim when he first thought of it, but I think perhaps it's a little underdeveloped.
As Morris points out, it's already been done a bit with American Gods (although we'll agree to disagree on the quality of the work).
I think a better way to expand it (as others have mentioned) would be to see gods in various personas/roles they have taken up. So not just professional wrestlers (i.e. WWE or whatever) but also as modern popstars, business icons, pro-atheletes, models, movie stars, and perhaps even more modern takes like influencers and podcast hosts etc. The amount of people who watch Tik Toks versus how many people would watch wrestling...let's just say if you wanted worship the former would be the place to go.
It would be easier to avoid this minefield though if there was no gimmick, if it was simply a book about gods and had a more elemental, esoteric, weird feel. I thought he handled Hades and Ethniu and even Odin quite well. It would be a shame to parody other gods and mythologies. While I think there is room for such things, and some gods might even suit the parody (e.g. Hercules) for some it would be a let down (Thor) or just inappropriate (Aphrodite). Just my take.
Supernatural sometimes went the gimmicky option and often it felt cheesy and a bit empty. Yes, sometimes it worked too but far often less so. I am not saying I want the series to be all grit and darkness either. A big part of the appeal of the series is the humour.
I believe Jim enjoyed some of Rick Riordan's stuff, particularly the Percy Jackson series, and he definitely payed some homage to it with Battle Ground. So I wouldn't be surprised to see more of that. There's been a few interesting takes over the years; Malazan, Craft Sequence, Lucifer (the comics that were a spin-off of the Sandman, and not the travesty that was the TV show - which I believe some found enjoyable but I found it quite difficult as it was such an awful departure). Roger Zelazny dealt with it several times in differing ways - The Chronicles of Amber, Lord of Light, Creatures of Light and Darkness. Each a fascinating take and quite different. Everworld by K.A. Applegate was closer to Percy Jackson but darker and more adult, but also an interesting take. Even the Almighty Johnsons TV show (a New Zealand take on Norse Gods) was quite interesting and often funny, although occasionally a bit lacklustre and a bit dated now.
This poem - The Egg
http://www.galactanet.com/oneoff/theegg_mod.html is quite thought provoking. Oddly enough, I also thought it had some parallels with the Dresden Files but that could be just me seeing things. Siddhartha by Herman Hesse was similar (and I suspect inspired Zelazny's Lord of Light).
Jim will of course do his own take, but considering the many takes that have come before, and the world he has created and the talent he has, I very much hope he will take this opportunity to do something really fantastic. And he really needs to get more into the "Why" that the gods have backed off. A vague "humanity needs to grow up" isn't all that interesting, to me. I understand he doesn't wish to offend but perhaps some background to a major event would be good. Relating it to Outsiders probably would make the most sense.