Well that's certainly a start, once USB-OTG is working that should be fairly workable, though still not ideal. I imagine there must already be a simple front end for it, hopefully one that'd be easy to port over, and work with only game controls. I'd lend my hand to it, but I really don't know anything about porting.
One possibility would be to add SFTP support in DinguxCommander, since that already has a GUI for manipulating files. Any volunteers?
As a workaround, it might be possible to use FUSE to mount a remote server as a local file system and then use DinguxCommander to transfer files. There is no FUSE support in the current kernel and rootfs if I recall correctly, but that's a matter of enabling it in the configs and rebuilding; it wouldn't require new code to be written.
It'd also be nice to get a package manger like apt or yum on it, could open up some nice Linux utilities and daemons.
Just having the package manager is not sufficient: all packages have dependencies and the only way you'll be able to run a package from a distro is to install all its dependencies as well, up to the libc. You could try to install Debian (I'm not aware of another distro that has pre-built packages for MIPS) in a chroot environment on the Zero, but it would be like installing two separate operating systems that share only the kernel.
There will not be a package manager in the traditional sense for OpenDingux. The mechanism we use now with a read-only rootfs image and self-contained applications is more reliable and a lot easier to support (but less flexible). We do want to have an application manager for installing, removing and updating applications that are packaged as OPK files.