I expected this kind of ending. Not much changed between the two girls and I doubt it ever really will. Still, I've come to expect this from Kodama, so it's not a big surprise.
Reo understands Meiko's true feelings now, and, in Meko's absence, came to understand her own feelings as well. Seems like a big change to me.
The main thing is that the relationship is still pretty toxic. Reo even acknowledges that she will lose sight of herself and that they can't go back to how innocent they used to be once they are together. The whole issue with the story was how their relationship had deteriorated almost completely. By the end, there is some patchwork done to "fix" their relationship, but in the end, it was still just a patch job; it didn't fix the underlying problems. Thus, I personally don't believe that very much changed.