Oh, actually a few other trainer classes came to mind.
If there is something like the rocket in R/S/E, I would like to be able to maybe go on the rocket and fight astronauts.
Another cool class would be teachers. (I don't know if we already have them, can't remember)
We can battle students, but we've never battled teachers.
Oh, and maybe someone like Looker, International Police person, or maybe just a detective.
This is kind of random, but maybe there can be some kind of body builder person? Working with machamp or something.
I was also thinking the main character could go to some festival kind of thing, and there are Clowns you can battle, or Magicians?
Yeah, I'm just thinking these up as I go.