So I'm trying to get my mixes more mono-compatible, and understand that using stereo imagers to narrow the sound can help with this (I’m using logic’s direction mixer currently).  I was wondering if a plugin exists that can do this dynamically.
 
By this I mean that it reacts to the stereo image like a compressor would, so that when it gets past a certain width threshold it starts to narrow it.  I realize using a dynamic EQ (like voxengo glissEQ or ozone’s dynamic EQ) in mid-side mode could sort of do this, but I haven’t found a plugin that can reduce a stereo image like this over the entire frequency spectrum together.  I feel like it wouldn’t be that complicated of a plugin to design, and would help a ton with getting your phasing right in mono.  So yeah, does something like this exist?