I like odd time stuff too (always have) but I don't like how they are being implemented; in RB you can't set the time sig to 15/16 and play a 15/16 realtrack. It doesn't line up and actually becomes a 7/8 pattern if you try, since the 'sample' (chosen chunk of realtrack recording) truncates.

Hard to explain, but I heard from above that this was the expected behavior. This concerns me.
Other wave files recorded in that time signature can be lined up with the time sig/tempo so a click can be used, and editing is much easier, etc. If odd times are expanded I think they should be marked in a way where they line up correctly for other use.

I do not work here, but the benefits are still awesome
Make your sound your own!