Although Pokémon is generally aimed towards the younger audience... the new writers are
fully aware most of their fan base is much older audience watching.
But we have to keep in mind that the anime is rooted to Japanese culture so, if Serena were to confess her love for Ash, it would probably just be "I really like you" and then maybe a hug... most likely no kissing, obviously for the kids and Japanese culture. There might be a peck on a cheek, though. Since that was in the 2000 movie.
Sephora is right though. Although we are all dying and curious to know what will happen at XY's ending. But we're going to have to wait unfortunately.
And we all have to keep in mind the new writers are the same from the Pokémon Origins special and they obviously have thought ahead for everything, including filler episodes. My guess is that they wanted to test the waters in the shipping itself (since the first lead female character to have confirmed feelings for Ash later on) and if it went well, they would pick up on the ship and go with what they originally planned for Serena if everything worked out with the popularity of the ship. In the beginning,
if they were testing the waters with the ship, and it didn't sit well with the fans then they would just drop the whole ship idea and say it was just Serena having admiration for Ash for helping her and just wanted to meet up with Ash to become better friends after seeing him on the news... (although that wouldn't really stop people that shipping Ash with Serena even if there was no crush lol)
If that makes any sense, lol. Just guessing with what the new writers might have already been planning before they were officially given the job while Ash was still on the Decalore Island trip.