I do like Serena, though. She developed into an actual character, perhaps at the expense of the others since most of the battling was against her. Still, I preferred that to having to battle both Cheren and Bianca in such a close period each time. As far as the team is concerned, I realize she's the first rival who uses a Pokemon that's not in the regional dex for her main team, when she adds that Clefable (Blue in FR/LG exists too, but I think that could be a special case). It's really a nice team, and it reminds me of Wally, in a vague way. Must be that Altaria. Or the fact that it seems to fit Serena better than Calem.
On a side note, I don't think Cheren's final team was that bad. Or Hugh's. Just that sharing Unfezant and the monkey made them look bad. The rest of their teams are great, though.