What would be so bad about rebuilding Ubuntu on top of Bionic, so there's only one libc, the one required by the GPU drivers, and the lighter one to boot? If Bionic is good enough for FIrefox and Chrome on Android, then surely it's good enough for anything on a mobile device.
Lot's of stuff - talk to Collabora developers who attempted to rebuild some common Linux middleware atop of bionic. It's very difficult, painful and upstream bionic has no interest to cooperate to help this process. So I conclude that it's a pointless time wasting. Mobile Linuxes should continue to use glibc and working on getting the drivers. Libhybris is a good tool that helps deployment until normal drivers will become more common. TL;DR - bionic is not good enough to replace glibc.
