Is it really that difficult to fit him in? I'd say it's the most common formation that top teams have used throughout europe for the last 20 or so years. A three man midfield, with one more focused on defense, one more focused on controlling the team, and one being a bit more offensive. Obviously there's a lot of overlap between them, but it's a very common set-up. Even we tried to regularly use that set-up during his time here, but we'd just have him as the controller while playing the likes of Mata, Lingard, Pereira, Mkhitaryan or Fellaini in that more attacking role.
I'd hardly say Matic and Herrera were 'superstars', but the three of them together were simply a balanced midfield with each player playing in the role that suited him. Surprise surprise, all three of them suddenly played extremely well (Pogba especially was brilliant) and the team as a whole was great and had the best results since SAF left.