Whether it be crop rotation, cover crops, or the need to supply farm fields with inputs, agriculture is not like nature.
I think that any cover crop can do some good. If you like planting polycultures, do it. But don’t let the appeal of the silver bullet, of the secret solution, cloud your judgement. Novelty entices the most sober-minded of us into thinking “this is it.” I still sometimes grow cover crop mixes, but also monocultures. Both are good, but as I found, and as science is confirming, cover crop mixes are not the restore-everything-to-as-it-should-be final solution we hope for.