I wonder how the plot will deepen >v>
So we can say that the song itself is a hint on Serena's side? Possibly. We're already 60+ episodes into the series and the XY arc is still breaking all of these status quos (as if that hasn't been said enough already). The fact that the ship and their stories are connected is already a good sign of things to come. It would be dumb for the writers to sweep everything under the rug especially when, clearly, Serena and Satoshi's relationship is a plot point for at least Serena's journey as a Trainer and a Pokemon performer.
I just noticed that Satoshi's character development has been more...subtle, if you may, compared to Citron, Serena and even Eureka's character development. So far, I've been getting the vibe that the XY arc is more about Serena than Satoshi
obviously not really, but I wonder when they'll start really focusing on Satoshi's side and how they'll handle his relationships, especially with Serena. All I've seen honestly is him catching Pokemon, winning gyms, saving the day...not so much on his personal side. We have a lot of that from Serena's side on the other hand.
I wouldn't mind if the XY arc ended with Satoshi traveling to a new region, as long as Serena's crush on him has some closure with it. Kiss on the cheek perhaps?
Sorry if a lot of these things have already been said and I'm just repeating them all.