Piano needs a bit more velocity, dynamics, unless you were goin for that kind of tone in it. Just a personal preference. If it wasn't a loop I'd say removed or change the first clap, it doesn't sit well in the mix for me until the piano comes in, maybe clone it, thin it, add reverb, but only for the first clap hit in the loop, and maybe automate it to become full, that could be really cool, but without trying it in the daw it's just an idea.. Claps slightly loud too, I like the synth you chose for the arp, very snesy/cavestory sounding.
There's a lot of room in the highend, but if you want a loop that's not too busy it's fine, the low ends really full with that piano though, seems odd, but just personal preference.
Overall I could see it being used commercially, I'd look into genesis pianos, or e pianos (fmdrive 2616 [or is it 2612?] is my favorite) and the like, it might fit the arp's better, not overpower it in the low end and clash less with the tone, maybe play with a bit crusher on it. Maybe play with a bit crusher or very slight overdrive on the clap, very sublle though, the clap just feels a little thick in the mix to me.
Overall I think it's good as is, just throwing thoughts and ideas out there as I have them, and it's been looping flawlessly as I've been writing this, so no complaints, just some suggestions. You're free to disagree with me of course, I've never had the greatest ears for mixes. Hope you like the review anyway, returning the favor^^
-strat