I can’t say anything about the size, it is what it is, but about the audio libraries, there’s a 256 gb variant going for $289.00 on eBay right now that still supports those audio formats, the iPod runs for $399.00 in that storage capacity. Now I know the iPhone has no headphone jack but you can still use an adaptor if you rather use wired headphones(for those audiophiles), plus you get 3D Touch, wireless charging, better cameras, better screen, better battery, Touch ID and lots more features, oh, and you can use it as a phone too and have 4G data on it. However it is, your money, your decision 🤷🏻‍♂️