Hey, no there is not really something to fix your model is fine! :) But for my personal opinion its a bit much material to store only 12 marker, i like it more minimalistic, on the other hand your model looks better instead. But because of that i would have to print 2 what means for me even more material and way longer print time. Like i said thats only my personal issues, and not because of your model. I just needed more slots with a faster print so i actually made a very quick remix to fit my needs ^^ (Don't mind the surface, i printed with 0.6 nozzle at max draft settings and way to fast and didnt took care about quali) ,tell me if i should add it as a remix.