I hear the songs of a lot of young singer/songwriters, both in Portland/Vancouver bars & pubs and on TV (my sisters watch all the talent competition shows), and I have noticed a couple of things about most of them. The chord sequences are very minimal, just two chords alternated between, back and forth, over and over and over. Relatively few up-and-coming songwriters seem to be aware of classic Pop song construction, with chord "progressions"---a chord, followed by a second, then either a third, or back to the first with then a third played instead of the second again. And really good songwriters, on the second time through the progression, replace one of the chords in the first transversal with an alternate chord, to keep things fresh, interesting, and seemingly unpredictable. And it appears that the "bridge" or "middle eight" section of a song seems to be either out-of-fashion or unknown to young writers. They would do well to study the songs of at least Lennon & McCartney and Brian Wilson, for a start.
Then there are the song "melodies". I put melodies in quotes because the line of notes used to sing the song's lyrics often barely qualify as an actual melody, being instead nothing more than the root note of the chord being played. Many, many songs have no "hook"---the sing-along quality of a true melody. This is nothing new---I immediately heard it in the "songs" on the first Blondie album. It's one thing to be a singer (if you want to call Debbie Harry that) or a musician, quite another to be a songwriter. The songwriting talent in The Beatles unfortunately made writing one's own material almost mandatory for a singer and group/band who desired respect from his/her/their peers. There are many groups/bands with a lot of singing and/or instrument-playing talent, but little songwriting talent (imo ;-).
Another element missing in much of the contemporary music that is popular with the masses is harmony singing, which is a shame. Harmony (and it's sophisticated cousin, counterpoint) is wonderful! It is still very much evident in contemporary Bluegrass music, one reason I listen to that genre. It's quality songs is another.