Whether it be the games, anime, etc., I much prefer the Pokemon themselves to any human characters. Looking at it from the perspective of "what would happen if one or the other no longer existed in the franchise," I'd be much more interested in following the Pokemon than the characters that the franchise created (which is why I think games like Mystery Dungeon have been met with certain levels of success).
There isn't much character development for the Pokémon, I don't feel, so I prefer the actual characters.
That's the unfortunate truth to the series, but alternatively its greatest asset. I'd love Pokemon so much more officially if they spent more time making the creatures interesting.
ON THE OTHER HAND...
Since they're all bland and generic because each Pokemon is part of a species and not an individual, it allows fans (like myself :P) to come up with their own interesting versions of the creatures (even within the same species). It's probably one of the most open franchises for fans to use their imaginations.
To answer the question though, I don't think I've ever cared about the humans, save for the Team Rocket Trio. As I always say, if I wanna play with kids in hats, I'll play EarthBound. Otherwise, I'm in it for the monsters.
Other Stuff That's Totally Uncool and Not Worth Your Time!
I don't find the characters interesting in anything I've consumed (pretty much just anime and the games--I did like the characters in the manga but each time I try to read it, I never get very far). They're pretty bland and you have to try so hard to force any real personality or development on them. That's fine for some people but I don't like to embellish characters THAT much to make me like them. (To be fair, the games have gotten better at character creation but it's still a far cry from making characters I'm really interested in meeting.)
So I stick to liking the Pokemon. They just create those and let them loose so it's very sandboxy. I can make my own character, give him/her their own Pokemon, and let my imagine loose with absolutely no restraints. It's a lot more fun for me so I don't pay the human characters in any of the Pokemon series any mind and I just concentrate on the Pokemon.