I think it would be cool if we could control our volumio device over Bluetooth instead of only over wifi, I am planning on making a portable setup so I can play hifi music on the go. I want to play music to my portable DAC (fulla schitt), unfortunately my cellphone does not support usb audio output, so Im trying to DIY it. I want to run volumio on a raspberry pi 2, read my music from a connected flash drive and be able to look at all of my music on my phone, a bluetooth manager would make this super simple, rather now I have to jump though hoops to host a lan server on my pi so I can connect my phone to that ontop of all of that I dont even know if that would work.
Tl;dr add bluetooth instead of just wifi connectivity 
You could make volumio a wifi access point, or share your phone data connection and tether to control your volumio device.
In my eyes in a medium-term horizon, volumino should check after boot, whether an ethernet connection is active. If not it should check availability of a wifi module and if no wifi credentials are stored it should open its own network for easy setup. As a nice side effect you could leave it like that if you plan to run it where no wifi is available.
An idea was to read a configuration file from the FAT partition with network settings so you could set it up before using. Pre load wifi as an access point and possibly all settings.
This was put on a side track and as far as I know never really left the idea stage. All of this happened before volumio 2 development started and there are so many changes in Volumio 2. Though this would still be a great addition I believe it shouldn’t have a high priority. Would like the addition of headless setup with preloaded configuration.