Doubtful, because they'd still be the victim of absolutely dismal narrative with zero characterisation. It'd be an aesthetic change only, which wouldn't fix anything.
You can have meaningful and interesting characterisation with younger characters; sometimes the development can be more believable that way, even if it isn't personally relatable. Nor does older have to mean darker and therefore automatically better...in fact darker often means worse, because it lacks any kind of subtlety and often relies on cynicism and shock value to sell its pointless suffering and angsty drama. Some of the best RPG stories out there have been coming-of-age stories, or stories of personal self discovery, that have worked precisely because the characters have been younger.
But there is this tendency to think that "more mature" automatically means "darker" when it is in fact the opposite - or it should be anyway - and this is a VERY common theme in RPGs...whenever you see an older character as a protagonist, there is going to be a lot of brooding, crisis of existential nihilism, badly written romance, and general misery that has no real justification or point to it. It makes for an interesting counterpoint when said character is a companion, but it's extremely tiresome when said character is the central protagonist.
...actually, the more I think about it, the more convinced I am that having an older protagonist is a bad idea. It'd either change nothing, or they'd be an angsty edgelord straight out of the mid-2000s, because Game Freak doesn't have any competent writers. I'd rather they fix the core issue of bad writing, rather than just slap a new coat of paint on it in the form of an older protagonist in a poor attempt to hide it. No thank you.
