The rival shall be your very fabulous friend who lives in a big mansion next to your small one. He is friendly, yet his ego is big.
Also, the new evil team shall be Team Croissant.
This kinda matches the rival idea I was working on for Pokemon Games I was designing for fun and to use in my artwork portfolio.
Nobody cares, but I'm going to ramble on about the idea now
Essentially the rival was a girl who's "default" name is Oregon. She lives in a mansion on the outskirts of town. Her father owns the regions equivalent to the Department Store, and her mother is a very well known contest judge. She also has very well-off relatives such as her uncle being a member of the Elite Four.
Due her upbringing and family history, she feels the need to prove herself, and wishes to do so by becoming a Dex holder and taking the Pokemon Challenge. She's not overtly mean or nasty to you, but she quite obviously looks down her nose at you and is very "entitled" and expects her journey to be easy, like it's written in the stars for her to be the best trainer ever. She doesn't even catch her Pokemon, they're all gifts from rich relatives.
Depending on the results of your battles with her, she will come to respect you more and learn that she needs to improve as a trainer solely on her own efforts, not by the resources of others. As such, the last Pokemon to enter her team is caught by herself (Also, it's the only Pokemon that changes depending on your starter, other then her own starter of course)
Obviously as I was working that idea, it's something I'd like to see, and I think it could fit what appears to be a French based Region quite well.
Regardless of personality though i think the next rival needs to be
- Female, regardless of player gender
- To be respectively tough opponent. Not enough that they wipe the floor with you, but assuming that some players will be very young she needs to pose around a threat to players of average skill who haven't overleveled their pokemon.
- Scaling difficulty based on your Won/Loss ratio against her, and her Pokemons levels slightly scale to match your own (No more then five levels though)
- Finally, a Loss should be a loss. If you lose against her, you don't get that battle again, and the story acknowledges that she won.
Oh and like everyone else seems to be mentioning, a female villain would be nice.