I have to be honest, I would just make G2 again. Maybe make them a little stumpier like G3. I would probably create something really similar to LPS, like a lot of Y2K-esc abstract buildings, everything is pastel or brightly colored. Maybe something like the friendship garden's gimmick from early G2? Like, connectable fences or some sort of obvious interactive play between them.
There would be way too many gimmicks as well. Every gimmick imaginable that I like at least lol. Flocking, tinsel, butterfly wings- just all the gimmicks. Seasonal/themed gimmicks would be fun- like every Halloween we could get a different toy theme and playset. Like let's say, a graveyard one year, a haunted castle the next, etc. New ponies, new merch for every wave of toys etc. oh and bring back fashion packs, I could get into a pony closet situation. Vampire costume, ugly sweater, aprons, tutus...y'know the works.
maybe a cartoon, but i think it would just be something really similar to TYT or Tales. It wouldn't have a solid cast- I would probably just cycle through characters a lot. I'd at least have most ponies made put as background characters. Uhh no real plot lol, it'd be slice of life/drama. Comics and other media would be the same. lots of songs
The tone would be really, really understated and casual. yes they're neon horses who bake cookies and play hopscotch. they like that kind of thing. all the critical thinking would be put into the story telling not the world building.
i guess that is it
oh wait uh, no babies and no obvious gender divide in design. sorry baby pony fans. Pink is a neutral I think