Very cool to see a MiSTer build that's focused on looking and feeling more line a console. The "cube" look that most current cases has certainly is an aesthetic of its own, but this will look much better in an entertainment center next to other consoles.
An all in one USB hub, IO board, CEC isolator, RAM module, SCART output, and even power switch is also very nice. Looks like it's very much intended to be a plug-and-play solution.
The only things that stands out as "sort of missing" things are a place to tuck in a 3.5" hard disk, and composite/s-video. And from what I've read on the forums, just converting MiSTer's RGB out into composite/s-video can never be perfect, so no dings there. With CD consoles becoming more and more common, a lot of people are
keeping a HDD permanently connected to their MiSTer. Another optional "cartridge" that houses a loose 3.5" disk and a small form factor
USB-SATA adaptor could probably fit in the top front semicircle.