The Cowboys have quite a few needs beyond better coaching. They need LBs (multiple), a FS, a run-stuffing DT, and o-lineman (start replacing the ones that are old and beat up). So, I'd SERIOUSLY consider trading Micah for some draft picks and players (some of which can be obtained in Free Agency).
This team is not one player away from being a serious contender.
Micah is great, but not impactful enough, to my eyes, throughout the course of a game. And in many of the biggest moments late in the game, he's just not able to make a play (though I do think part of this is because Dan Quinn is on overrated DC at calling and designing defenses).