Gwai Lo Dan
3rd Black Belt
You mean the same stance (wide, fully bladed, hands low) that folks like Steve "Wonderboy" Thompson and Conor McGregor use? I think it's been demonstrated that such a stance can work effectively in MMA by someone who understands its proper use.
Personally I was thinking of the stance at the end of taegeuk 5 as an example.
I'm not saying a backfist to the face wouldn't hurt, but IMO there are better choices then ending up with your legs crossed in front of an opponent.