I know this is maybe a bad advice...but when I don't like something...
better to start from scratch (I don't mean your character - he's really overcool, keep it
)
I just meant the composition - but sure it's yet a lot to re-do 
Try more compositions...till you find the one you really really, I mean really dig !
Just suggestions from a bad "compositioner" ^^'
But I can guess you'll have better advices from master on here 
Good luck !