I'm glad the new girl is being welcomed by fans. I could not stand May to be honest and that was the nail in the coffin which made me give up on the series as it continued. And from what I saw of Dawn, I don't think I'd like her much either...

BW2 feels like eons ago haha. I do recall one or two generations did have leaders move up to the Elite Four while introducing a new leader. Maybe HGSS did that in their remake? I'll have to go read up on it though. But I think the less complicated the better, I guess it depends on the pokemon Ash wants to train or focus on, but then again as a gym leader, didn't Giovanni have a variety rather than a type specification? I assume it could be up to the leader to decide if their gym has a theme or not.