3rd gen's overuse of trumpets really annoyed me. I'm glade they're gone for the most part.
You want to complain about the overuse of trumpets? Try playing any Touhou game. Er-hem, back on topic, I do have to agree with you there, and it was probably part of the reason I found most of the R/S/E battle themes rather bland...
Anyway, the 5th gen games have some really great music, which ends up being very fitting for many areas. However, there is one area that stands out to me in awkward music selection: the Desert Resort, in which plays the same music as Wellspring/Chargestone Cave. The music is fitting for a cave, but a desert? That always struck me as kind of weird. Made me wish they had incorporated a more desert-sounding theme, like the one from R/S/E for instance. They could've done a similar thing to Route 4 as well.