Cuuuute! I think it's about time they actually do something like this. Even though it's slightly boring that they made Serena's crush on Ash a main part of her character.
The crush itself doesn't define Serena's character... Her whole arc was about a girl who really didn't know what she wanted for herself, a girl who always gave up trying because it was hard, someone who doesn't like the path that was laid out for her but does nothing to change it. The arc was about overcoming her sloth and her fears... learning to dream of a future that she'd want for herself, facing the hardships that comes along the way, facing the problems not only for herself but for her friends(And Pokemon). The phrase "Never give up until the very end." becomes her mantra and it's what defines her character in the end.
The girl who always gave up, never dream't of anything for herself... Learns to dream to fight and to never give up. Her arc makes her so relatable and so lovable that she's become my favorite Pokegal.
Satoshi/Ash was the catalyst of starting her character development, she likes Satoshi sure... But that's just a trait of hers.
But it completely goes against the main theme of the anime, which is Ash's bond with Pikachu. Romance would only distract it, and it all falls apart. That's why they didn't have shipping in mind when they were considering kicking off either Misty or Team Rocket for the Hoenn saga.
The older series only had one theme... discovery and adventure. Ash/Satoshi bond with pikachu and other pokemon was more of a plot point.
The Kalos saga had several themes... one of which is never giving up (As seen in all three of our mains Arc's). Meaning of victory and what (I) fight for (Ash/Satoshi and Alain arc). The value of experience over talent (Shota's Arc). The Value of dreams (Serena and Clemonts arc). What makes a hero (Ash/Satoshi and Greninja/Gekouga's arc)
these I feel are the most important I feel.
They chose team rocket over Kasumi/Misty tho... which is a clear indication that the writers never intended for any "Romance" between Satoshi and Kasumi. Well not unless you count the cut scenes from the Pokemon Bid for Power (Originally meant to end the Anime's continuity) which heavily implied that Satoshi and Kasumi will end up together... and the movie itself is Kasumi telling the story of when she met her first love to her daughter.
I can't find the original japanese trailer where the scene is shown tho...
