I am a lover of scrappy quilts and basically only make scrappy. There is something about the look that just reads old and loved to me. I'll buy complete fat quarter bundles of a line and only yardage for the backgrounds and border most often.
I love your quilt, but, I think I know why you might be questioning it. It's hard to tell, but is the denim colored sashing a plain or a print fabric? I generally will never use a plain fabric in my scrappy quilts. I might use one the "reads" as plain from afar, but if you look at it closely it has some sort of print. Also, the outer corner squares of your blocks look to be the same color as the denim sashing you are using, so when all put together the block changes it's look (the corner squares blend into the sashing).
None of this is a bad thing, I'm just wondering if these two things might be what is making you change your mind on liking it. I'd say continue on...your son will love it and will never see what you see, BUT, as someone who cannot work on a quilt I don't like, I "might" change it if it bothered me too much. Changing the color of the sashing might be what makes your heart sing.
Whatever you decide, it will be wonderful. Scrappy quilts are the best (to me, anyways).