OK, in an unusual move, GW adopted what I was mentally wishing for as a "pie-in-the-sky best possible case" approach for the new releases:
https://www.warhammer-community.com/en- ... -releases/
The 16 returning warbands, pretty much as I predicted as the number was suspiciously divisible by four, will be in 4-to-a-box sets by Grand Alliance (which is sub-optimal for telling new players "this is all you need to get" but does produce a manageable number of SKUs - but new players who want a cheaper buy-in would be able to buy the new warbands individually I guess), with a single card pack sold separately with all 16 of those warbands' cards for people like me who already have the models. Actually I'd guessed this would also probably be four packs, so that's a nice surprise. All the other warbands will get pdf rules, and again it states the only time they don't want you to use them is in official GW events - I guess this is pretty much exactly what they're doing with Kill Team too.
The yearly roadmap is also slower than it's been, which considering one of the big complaints over the past couple years had been "there's too much product to keep up with" is also a good move. This year there'll be two additional warbands (for 20 total) and two new rivals decks (for 6 total) and in 2025 it looks like they'll release a single warband and a single rivals deck per quarter.
Also quarterly balance updates, but they've never been too bad about giving us balance updates periodically, it just makes it an official part of the schedule now.
It's not on the roadmap but I would
guess a new corebox about this time next year, with another set of four grand alliance boxes that'll stay on the store for that next year - they do say that some number of the old warbands that aren't in the initial 16 re-releases will be getting re-releases in the future, so presumably that's with warband rotation at about that time.