I’m hoping to see direct SD card / DSLR import to third party apps like Lightroom, skip the need to import via photos would be a big step forward. The ability to export to a usb device would be even better, essentially retire my MacBook for photo editing if we got that. I’ll keep hoping but I’ve a good feeling about ios13!
I have read rumors that bypassing Photos and importing directly into other apps (like Photoshop or Lightroom) is one thing they'll likely add, but no mention of exporting to a USB device. I'd love it if they add full read/write access to external storage.