I thought about this question for awhile...
Manga: This is fine the way it is. I don't think change is necessary.
Anime: Repetition, repetition, repetition. Please, come up with a better plot. Even though Ash is the main character, I think he also may be one reason I don't follow the anime as much anymore...he's a dimwit, he resets his power every region, etc. etc.
Games: I...don't...hate the games. Generation IV bored me out though, nothing real special. I was all ready to give up the games until Black and White came out. Now it's all good.
It's probably best not to go by my opinion though. I'm swayed by personal preferences. I don't hate on any generation though.
Regions in order of preference: Hoenn, Unova, Kanto, Johto, Sinnoh. :/