Like someone said, composition was weak except on a couple, try to seperate the subject from the background, Don't try to simply fit in the rider but whole scene that's around him, and less trees (if you know what I mean)
The ones he imbedded aren't what I'd call excessively saturated. Sometimes it makes the colors more interesting and the subject stand out if the background isn't very colored. Other times, it's just a trap that people who don't know much about photography and just got their first DSLR and photoshop fall into.
I've been using photoshop for a few years now, but I just got my DSLR. I didn't take offence to anything you said so don't worry. However it's just a look that I like. Call it amateur or whatever, but to me it's just personal preference.