It's true about Hugh. The reason the Purrloin story doesn't really work is because you feel no personal attachment to it. It's just a random Purrloin to you. That's what the game was lacking with Hugh, without seeing it happen you can't really believe that it's that significant. I think a way to make Hugh better would have been to introduce Purrloin at the start with Hugh and his sister. See them bonding etc, by the time you get to face Cheren you find out the Purrloin was stolen (it can still happen and evolve through the course of the game). You then feel personal motivation - you want Hugh to find the Purrloin. Then, if they forced Hugh to battle it during the game and he didn't know - now that would have made Hugh less irritating and more Pokehuman.
But consider the following: what if the lack of attachment to Hugh's sister's Purrloin is intentional? Compared to BW, which involved two "chosen" characters brought together by "destiny" to battle with the legendary Dragons, B2W2 had more of a focus on neutrality.
As the protagonist (and in order to get the game going), you can't say "no" to Hugh's request. And if you did, wouldn't that feel kind of wrong? He's your friend and his poor sister's Purrloin has been stolen. It's nice to help out--that's the right thing to do... right?
As the game goes on you meet various Gym Leaders who are more than capable of dealing with Team Plasma--most of them have done this once before, after all. But you've already started your quest, so you may as well follow through with it.
But then you meet with Marlon. Marlon, unlike the other Gym Leaders, wants nothing to do with Team Plasma. Maybe that seems really inconsiderate to you--and that's fine! But just take in what he says:
Marlon said:
"Listen, 'K. Believe in somethin'! Searchin' for stolen Pokémon is fine! Keepin' Unova from bein' iced over's fine too! It's all good. But think 'bout why you're doin' that. The strength of your beliefs is what gives you and your Pokémon power!"
Marlon doesn't get involved with Team Plasma because "It's not [his] style to go around decidin' Team Plasma's bad without thinkin' 'bout it just 'cause everyone says so!" Team Plasma hasn't bothered him, so why should he get involved?
Isn't that the same scenario for you?
You don't even know Hugh's sister's name! And you're getting all wrapped up with this evil gang who wants to ice over the region for
her and her Purrloin? Maybe you do it out of a sense of righteousness, that helping others is naturally the right thing to do--
and that's fine! But think about why you're doing that!
Whereas BW made you question the morality of keeping Pokémon confined in Poké Balls for the sole purpose of having them do battle with each other, while also encouraging you to try and see eye-to-eye with people whose opinion differ from yours, B2W2 made you question the things you do. In B2W2, you're a
neutral party. Team Plasma is on one side and the Gym Leaders (and Hugh, who wants to retrieve his sister's Purrloin) are on the other, fighting over the safety of Unova.
But why are you there? Do you even really need to be involved?
So ultimately I can't bring myself to dislike Hugh. I didn't find him annoying, I thought he was energetic and fun (and, to be honest, I didn't find gen 4's Barry annoying, either), and it was nice to see him help the old Team Plasma at the end of the game take care of lost and abandoned Pokémon (since that's obviously a matter important to him after what happened with his sister). Hugh essentially act's as the story's catalyst, and it's a story I enjoy because I love the juxtaposition of B2W2 being more focused on neutrality whereas BW centered around a plot based on "destiny," with both featuring many binaries.
I'd say Cheren is my favorite, though, because I
love his development throughout BW and I was so happy to see him return as a Gym Leader in B2W2! All the extra time you get to spend with him really adds to his character and it makes me very happy!
But I like Bianca, too. She may be my least favorite because she isn't
as involved in B2W2, but she still had superb growth throughout BW and it was nice to see her again trying out being Juniper's assistant.
And Unova accepts all sorts of different people, so I'd never send any of them away!