It has it's positive ways..
Well I agree with Zaine, this indeed sounds just like an midi file, better instrument samples are not bad idea, and one really big thing that is missing is Percussion! Percussion on these are one of those most important sections of my mind, listener can more easily listen song, because there is going simple percussion and that's the easiest way to follow song, same on there other instruments combined with percussion is the best thing on these really.
Well I don't blame for using straight midi, I use it too sometimes, but mostly I just borrow main melody, backups and bass and add my own things on it, and there's it, but I don't blame yo for using midi file to do this, (If you used of course)
Just keep it going! More you make, more you learn to do =) Keep going!!