If they make the move to Ubuntu, it is likely to be for some reason other than stability or drivers. The kernel you build controls the drivers available to you. Also, the only time Linux stability changes is dependent on a) what version software you build (and its development state - alpha, beta, or production quality code), b) What you build with (there are some broken GCC builds out there), c) how you optimize the code while building (over optimization can cause its own problems)Stability will be increased if BT moves to Ubuntu, as well as driver support (i would think)
Also while they would change the base, the distro will still be very heavily customized. Currently Slackware is used as the base, and has provided a good base for some time.
But it would be interesting to see if/why they would change the base distro.