This song is...strange, really. The chord progression is good, but there's always one chord that totally doesn't fit. Same goes for the melody. I really need an answer to this question: WHAT IS THE KEY?! It sounds pretty random, but I'm pretty sure you must've used SOME structure in this song (although you say you want your songs to be less structured).
Also, for a song that's 6 minutes in length, it's very repetitive. Only the end offers a bit of variation, but that's mainly it. If you wanna make larger songs, make sure that they don't sound the same all the time.
Last thing, turn the pad's velocity down, it's a bit too loud IMO.
Hope I was helpful. :)