Using my own Verizon Note 3 as an example:
When I updated to KitKat 4.4.4, the ability for apps to write to the SD card was mostly gone (other than the stock file manger, for example). This was a pain.
When I received the Lollipop update, things improved significantly, as apps were able to once again write to the SD card - not anything, anywhere, but there was now some type of formal structure that enabled apps to write to certain locations on the SD card. And if I'm not mistaken, Apps had to be written or updated in such a way as to take advantage of this capability.
So I'm assuming/hoping that the G4, with Lollipop, will not have practical problems in this regard, at least for Apps written or updated for Lollipop.