It would have to be an option, because it would also disable the ability to solo a midi channel, then switch instruments (that are routed to different audio tracks) by changing the send channel on your controller.
That would be very bad me thinks :-)
I think the answer to this might be "Don't Solo the MIDI Channel".
Sound crazy ?. Try it.
Soloing the audio track also solos all the MIDI tracks, because it too, has no real way to tell which MIDI track you might decide to send data from.
I think it's a case of choosing which you solo (audio or midi), and then that's the group you have to take notice of. Maybe hide the others ?.
To me, the current behaviour makes total sense, and I think would essentially "break things" to change it.
Cheers - Cliff