If it's post Super Hero, then deaging the cast makes sense since almost everyone can punch a universe in half so de-powering them a bit will make fights more interesting
Also it's a good sign to know that this has been in production for a while compared to Super that was just forced out a few months after the official announcement
I have to wonder if that was a Toei idea for marketing to younger kids or a Toriyama idea where he went "I'm bored of drawing adults! I'll make them all young!"
I know one case like that was involving Jiren where they wanted him to be more outspoken like a superhero, but Toriyama cut in to say that Jiren shouldn't talk and must always be stoic
Toriyama: "Here's my version of GT! You like?