If we can make administrative cuts that would not impair the abilities of our armed forces in any way whatsoever, I'm all ears. If we can streamline operations and use the saved money for additional development of our military, I'm also open to that. Unfortunately, closing military facilities would, I think, run contrary to these criteria.
I just don't think I can endorse sending a committee off to investigate our military with the specific mandate of figuring out which facilities we can close.
The idea behind BRAC is to do what you said in bold. BRAC began in 1989 and did several more rounds in the 1990s in the wake of the Cold War to close bases that were no longer needed due to the collapse of the Soviet Union. The focuses of a commission would be to better integrate active and reserve unions, rearrange forces to be able to act around the globe (say, closing or reducing bases in Germany while enlarging bases in Japan), make the military more flexible and agile, improve cooperation between military service branches, and convert or remove unneeded capacity.
We're finding what facilities we can close, yes; that frees up funds in the budget from things we don't need (namely, facilities that are no longer necessary in our changing global environment) and would allow us to reallocate those to things we do need or where the money would be spent more effectively (more research into drones, or more destroyers, that kinda thing).