I like most of them but, I'll just state how much I like them
Kanto: Haven't played this gen but read the manga
Lorelei: I like her ice type specialty and her personality.
Agatha: Being Professor Oak's rival? She must be hard...
Bruno: Hmm...
Drake: First Dragon Type Elite Four... okay, fun.
Johto: Played
Will: He looks weird but he isn't easy to face
Koga: It is cool how in HeartGold and SoulSilver that he doesn't just specialize in poison types
Bruno: You again?
Karen: Don't mess with Karen.
Hoenn: What is this region again? (OOH, Champion Steven is in this region! But who are you?)
Sydney: ...
Phoebe: ...
Glacia: ...
Drake: ...
Sinnoh: My first completed pokemon game
Aaron: A bug type Elite Four? Now that's cool.
Bertha: Perceptive... the earthquake attack is frightening to my only high level pokemon...
Flint: He knows his stuff about being a pokemon trainer and a person
Lucian: Smart, yet hard.
Unova: Hello? Do you have Black and White? Sold out? Are you serious?
Shauntal: A journalist... huh?
Marshal: Why do you remind me of Bruno?
Grimsley: That Bisharp... it's strong in the game and anime
Caitlin: Weren't you the crybaby in Sinnoh? Ooh, I remember you from battle castle!
Kalos:
Malva: Thanks for welcoming me. Did you actually defy your master Lysandre and gambled on brats? Good for you! High-five!
Siebold: Mm, seafood, can you cook any for me right now?
Wikstrom: Okay, it's an honest battle. No, stop, no poetry please.
Drasna: Thanks for the welcome! I'm from Sinnoh too! Ooh... I was going to use a fairy type, good thing I didn't for that first one