Thanks for the replies! Yeah I have done that workaround before with the grouped control linking of two mono compressors but I feel it has some drawbacks. it's not so much that its a bit cumbersome (which is annoying but not a real problem), but actually its more of a problem that it puts some restrictions on how you can apply the compression. There are compressors out there that accept stereo sidechains and have a lot of controls in terms of how to interpret that stereo sidechain signal and how to apply compression to the stereo signal being compressed. With two multi mono compressors you are stuck in a mode where the left channel and the right channel are being compressed completely independent from each other unless you choose for the sidechain to be the same signal (either stereo summed to mono or pick the left or right channel and sidechain that to both). If you had a stereo key input you could do so much more.
It's a pretty particular request I am finding from looking on the internet, but if anyone else is reading this and is hoping avid will add this feature, I put in the idea request at pro tools idea scale, here is the link please upvote it and give it some internet love!
http://protools.ideascale.com/a/dtd/...ut/262997-3779