Mr. Mearls, I think the eventual success of your 5e variant will depend entirely on how you write your stealth rules!
It seems to be the hardest thing to do in a gamebook!
Ha! It's definitely tricky, having been part of it for 4e, 5e, and in my own designs.
And I know you're joking but FWIW, in my own games I took a cue from video games and treat it like a terrain feature. I've been using these rules for a few years now.
Shadowed terrain lets you hide. It has a distance attached to it. You can't hide from creatures within that distance.
I also adjusted darkvision - it treats darkness as dim light within range. It has no effect in dim light or bright light.
Areas of dim light are treated as shadowed 15 feet. If you hide in an area of dim light, a creature needs to be within 15 feet of you to automatically spot you. Otherwise, it needs to make a Wisdom (Perception) check to find you if you are hidden.
The fun thing is then varying it up to account for creature size or type. I was inspired by a hike I took a few years back, where the trail cut through an area with lots of thick undergrowth. A thick patch of ferns that are knee high to a human might be shadowed 5 feet for Tiny creatures or Small ones that are prone, while it has no benefit for other creatures.
On top of that, you can do creepy things like a misty graveyard that undead treat as shadowed 5 feet, or an area around an unstable psionic plinth that is shadowed 10 feet for psionic creatures (the psychic static messes with non-psions' senses in subtle ways that they can't consciously notice until it's too late.)
Also, before anyone takes this as a dig at the 2024 rules I am personally excited for them and love what I have seen of the PHB. The rules appendix alone is worth the price of entry. For me it's great stuff.