i think so many of my opinions on discussions this sub-forum had recently (level scaling, HMs/field moves, TMs etc) warp back to me wishing the badges were as relevant mechanically as they are in lore. like, they Should be doing something beyond being glorified checkpoints (which they do in the pre-alola games by unlocking field moves!)
alola found a way to make trials and grand trials feel important and you just get z-crystals you don't always use, so gym badges can definitely feel that way too, and even better since you can avoid the literal checkpoints alola had.
Contrariwise, I'm incredibly glad Gen IV did away with the stat/type boosts each badge conferred in previous games. Neat as they were to read about in the game manuals, I'm always kind of "meh" on any boost that's only relevant in the main campaign and tbh with how much easier the games have been steadily getting further advantages are really not necessary.
But yeah it would be good for badges to feel a bit more meaningful. Obedience is fine (and if we're going to have open world games it should be done properly and be based on the number of badges, not the badges themselves) but I actually think it'd be really cool if they returned to that concept of signature/secret techniques - have the TMs gym leaders give out contain moves that no Pokemon (or very few) learn on their own and be explicit that some/all of these moves are created by them. It'd be a thematic callback to HMs in a way as well as the earlier games since it's "a move you can't use until this particular gym leader is defeated".