It would be great to have a "Match Source" option for audio. This option would be great for when you're transcoding footage or making proxies.

A perfect example of the usefulness of this:

When you are making proxies for custom aspect ratio or anamorphic footage, you need to create a custom export preset. It's very easy to click "Match Source" for the video and then retain the aspect ratio lock and choose a lower resolution like a 720p equivalent. However, if you forget to choose the correct audio channel setup, like if your clip has 5 channels of mono, and you leave it on the default of stereo, the proxy will not attach because the audio must match.

It can be very frustrating and a huge waste of time if you then have to go back and re-export all those files.

Would be great to eliminate the question of what audio configuration you need in those cases...