Not too sure what the missing feature or bug is but i've not had too many problems with Sofarun 8.0, usually if a game doesn't load under that I use MglOCM instead & that works 99% of the time, I can't get Diced to work on either though so not sure if that is a Rom Loader or FPGA issue.
Many DSK games have poke -1,170 in their basic loader that causes ram to not be mapped properly and crash games, you need to edit the loader to use the universal poke (a quick Google on msx universal poke) instead, some dsk do not load well with sofarun but load well if you use nextor and mapdrv instead... Rom homebrew games like diced might not have their types being recognized properly, so forcing different types instead of auto detection works best, Nikkiriky's routine that is used by Sofarom is amazing but it is impossible to be perfect, so sometimes it misjudge the type... Never tried Diced on my SM-X though, will check that later, if nothing works, report to KdL so he can investigate 
I don't have many DSK images on my SD Card, so not ran into any issues other than Laydock Nagoya Version freezing after the intro, thanks for the tips about the loader/nextor/mapdrv, will have to give that a try when I run into issues
Sofarun recognises Diced as ASCII16, if I change it to the correct one, Konami mapper it will reboot the system, MglOCM recognises it correctly but will then go into what looks like a boot loop with the screen flickering.