Infact yes : as a singer and sax player, I’m not so keen about foot pedals, and BB pedal/buttons are a little too strong for my old fingers. But I love the BB concept, so I’m developping for my needs a full controller interface on a portable PC connected by MIDI, extending the possibilities of the BB.
That’s why I need some returns from the BB… And the time signature is very useful when you want to compute the current measure/beat, as BB is only sending MIDI clocks every 1/24 beat… So if signature is changing during the song, I’m stucked… 
Infact it would be great that the BB send a simple CC (103?) at every start of a measure (with the signature inside). It could even send a CC102 at the same moment. Even if the part is not changing. It would be very valuable information for an external controller. See here :
Here is what my program looks like now, and it works pretty well, connected to a very old Mini-ASUS (that belonged to my wife, hence the color… ) , with the whole keyboard available for shortcuts 