I find it interesting, the parallel between new American music and new Spanish music vs. "old" American and Spanish.
I've been listening to Spanish songs for many years now (Fruko, Elvis Crespo, Grupo Mania, Machito, etc). The same evolution.....very little melody or musical structure as compared to songs of old where the melody stood out so well you could sing the song to yourself the rest of the day and remember every note.
I don't listen to today's Spanish music at all as it's bordering on Punk, Hip-Hop, Rap, etc. And that's not just the opinion of one Gringo. I've talked to many old-timers (Spanish) and they too miss those exciting Merengue's, Salsa's, etc from the 60's + where you could actually tell one song from another.
But I DO like listening to modern day bachata's. There's even a "bachata" dance style on arrangers.