I personally would recommend that people do play it, but as far as Drew and the feature goes, I'm not sure it's necessary or appropriate. The format of it all, from mission structure to cutscenes, just doesn't seem to lend itself well to what they're doing. I think they can skip it without too much trouble.
Now if Drew ends up deciding to play MGS5 in the future, I might argue that Peace Walker is important to his understanding of it all. But we're not nearly there yet.