But then they would lose customers who like to use 2x microSD. It is very clear why D&A chose to compromise with 1x microSD + 1x SD, in the Calyx-M - because it is an excellent compromise without taking much more space than 2x microSD, but still allowing lots of expansion flexibility. The Calyx-M may not have been a perfect DAP, but I think they absolutely nailed it, with the card slot decision.
Some people have found that simply turning Mojo on its edge prevents thermal issues.
I understand some people getting frustrated by thermal shutdown, but 95% of Mojo owners do not experience that, and it is easy to forget that Mojo is using vastly more silicon horsepower to process the digital signal than most other DACs on planet earth, and in a tiny case size.
As for windows losing handshake with Mojo... I'm honestly not sure whether Mojo is to blame for that, or...
(bold and font resize by me) I think 2x microSD is acceptable, although I agree that 2x SD slots would be much nicer than 2x microSD slots (because SD is cheaper per gigabyte, and you can still use microSD, with an adapter, if necessary). So, not a dealbreaker, but I think iBasso would interest more potential customers, if they made the effort to squeeze-in fullsize SD instead of microSD