While I like Serena's development as a Pokemon Performer, a bit reminiscent of Dawn's development as a Coordinator (notably both lost their first time, felt absolutely crushed, but vowed to become better and did), I do have a problem with her relationship with Ash. Basically, due to her having a (early) childhood crush on Ash, she's always accepting of what he does. And since they don't want her to ever disagree with what Ash does this has caused Ash to pretty much become a bit of a Gary Stu. Yeah, Ash is still a bit thick but have you noticed he hasn't made any major mistakes outside of a wrong battling strategy, or any mistake at all? Now remember in previous seasons where Ash would make mistakes. When Ash made mistakes the female companion was usually the first one to call him out on it, sometimes ending up in a fight with Ash defending the goof he did (and might become the theme of the episode where in the end they make up). But since in Serena's eyes Ash can do no wrong, the writers don't want to make her look bad so Ash has to be a perfect role model.
"Well that's not a bad thing, it's showing Ash is maturing". Yes and no, you can argue that but the problem is Ash didn't mature from his experiences, he was matured by the writers to make sure Serena doesn't look bad for seeing no wrong in him. It feels artificial, like we're reading a journal Serena wrote and she purposely left out the parts of Ash goofing up. This has also sort of made the group dynamic feel a bit stilted. Everyone agrees with one another (aside from the occasional sibling shenanigans between Clemont and Bonnie), only their quirks and goals separate them personality wise. When Ash would argue with his female companion about something he did I felt a strong dynamic between them, a confirmation of their personalities and how they view things. And I also feels it makes the group stronger as they need to accept each other's faults (and throughout their journey it provides options for how the characters will react differently in situations). It also makes each character feel more independent. Ask yourself this: how do you think Serena would act if Ash did mess up. Say Ash was goofing around and accidentally broke Pancham's glasses and Pancham is now really upset, how would Serena respond? I honestly don't know, she'd of course calm Pancham down but how would she talk to Ash. Would she yell at him? No, that doesn't seem like her. Would she be forgiving of him (as in before fixing the situation)? Maybe, but that wouldn't be fair to Pancham, her Pokemon who's care should come first. And what about when Ash's journey in Kalos ends? The way she has acted would make you think she'd follow Ash to Alola and if she doesn't would be a out of character (sure you can justify it, but it would be pretty weak).
(Bitch, there's only room for one girl is Ash's life...)
Going back a bit, thinking about it there's only one group moment I can think back to did I feel there being an tension between the group, and it doesn't involve Ash and Serena. At the beginning of
XY103 "A Cellular Connection" it's evening and Ash & co. are eating dinner. Bonnie is worried about Squishy who ran off after encountering Team Flare last episode and, after Ash, Serena, Clemont fail to ease her worries, tries to run off to look for Squishy. Clemont grabs Bonnie's arm and refused to let her go, yelling at her she could get hurt, and Bonnie breaks down and starts crying. It's a very strong group moment, high emotions and showing both Clemont's and Bonnie's personalities and how they clashed at this particular moment... and I think it's the only moment where something like this happened. And this is episode 103 of the XY saga, out of all the group moments there were only this one really stands out to me in terms of character interaction. Actually, wait, I lie, or rather I should specify this stands out to me in term of HUMAN character interaction. I just now remembered all the little squabbles Ash & co.'s Pokemon have, in particular Chespin and Pancham, which helps flesh them out. Or how about Eevee being afraid of everyone except Bunnelby, that also creates group dynamic.
Tl;dr: Serena's essentially submissiveness to Ash has drained personality from the group dynamic. Serena sees Ash in doing no wrong, thus to not make her look bad he needs to be written with no major faults. This has resulted in characters needing to fall back on quirks and their goals to flesh out their group dynamic moments. This is also doing a disservice to Serena's character as it's taking away moments she can prove she can be individual from the group if they do something she doesn't like and also if her and Ash part ways at the end of the XY saga (or ever) that would be out of character for her. I get a stronger dynamic from Clemont and Bonnie, both comical and at one point serious, who you do see butt heads but in the end are siblings so they quickly make up or sweep it aside (or in the serious moment confide and comfort each other). Even the Pokemon feel more dynamic as you're always seeing shenanigans between them during group moments.
