I’d say that most of the MO world is to the left of R’ Willig and R’ Schachter, the same way we were all to the left of R’ Chaim Kanievsky. They are huge gedolim, so the majority of ALL frum Jews are to the left of them.
Aveirah, please define what you mean by left MO, as opposed to centrist or right MO. I expect we’d find that we actually agree that there is an element that is separated from Orthodoxy, despite calling themselves Modern Orthodox. I highly doubt you’ll find any Rav who supports the things that this group does, other than possibly YCT “Rabbis”, who don’t really count.