There is a new standard for the SD cards... SDXC just about these days.
The Windows support is located in update:
exFATExFat is for insanely large storage volumes... hardly needed for audio purposes.

If one should theorise...
Usb 3.0 port would be nice in a next gen "device", lots of chip options:
Intel, Nec, ASMedia, VIA, TI, Renesas that I'm aware of.
A SSD drive bay Maybe... but why? A properly executed USB3.0 port would rule!
Internal multicard reader thoughts...
Much better to add a USB 3.0 port, as it is usb 2.0 compatible as well...
Lots of docs and hubs and card readers out there... that connect via usb 2.0 and in the future usb 3.0!
My 2 cents..
Imp.