Actually I do have a KitKat 4.4.2 phone, Gummy ROM, and I've got over 3,000 MP3s on the SD, as well as videos, photos and documents. Tthe internal storage is for the apps, some of which can also store their data on the SD, if desired, e.g. Autonavi off-line satnav which I use. The phone does USB OTG, but at moment I don't have a cable.
That goes back to what Medion said and the description of the XML fixer he posted -
"NextApp SDFix will modify the configuration file located at /system/etc/permissions/platform.xml to allow apps to write to the MicroSD card. Specifically, SDFix will add the Android UNIX group "media_rw" to the WRITE_EXTERNAL_STORAGE permission's configuration."
Many custom ROMs are adding that one value to that one line in that one file as a matter of course.
Without it, you can still use your external SD card for music in KitKat.
With it, power users (as Medion calls us) can still access things as before, including on-board file browsers having write access everywhere.
Due to the combination of more bad guys attacking the largest mobile OS and many believing that the sky is falling, many people demanded more security, so enter security-enhanced Linux (SELinux) stage left. (And Android is a real-time embedded Linux, always has been, going back to the Android beta released in November 2007 by Google, having owned it since 2005.)
And that's what this and a lot of other complaints stem from - SELinux and corporate and consumer security concerns.
If you want more security, you're going to have less access - and it's always been that way on computers.
But as for media being usable on external SD card storage for unrooted users - yes it is, you just have fewer ways to get to it.
But you're not limited to Google media at all.
If this is broken for anyone, complain to Google or just root and solve the problem.
So long as this is associated with the new security protocols, I doubt Google will listen though.
If you don't like the strictures of SELinux, root and modify as you may. Chainfire was in the news last week leading the cause of truth and justice on that.
That sucks for people who don't want to root or can't, but there it is.
Jerry at Android Central said what Medion did pretty well too -
http://www.androidcentral.com/kitkat-sdcard-changes
While I was uninformed on the details, my original points stand as stated -
This isn't necessarily an issue, there are limits now due to security, more models are coming with the return of the SD card.
And neither Samsung nor Google nor any other one hardware supplier represents all of Android.
Android is about choice - our choice.
It's not about who sold the most.
The market demanded SD card access so it's returning.
SD Card Access 2.0 has some wrinkles.