McKennie is doing almost the same as Ramsey. The impression here is that the Welshman is having a bad season, while McKennie is having a very good season. The reality is that they are doing the same.
6 goals+assists for both of them, with McKennie playing 267 minutes more. Ramsey is making more passes per match, more crosses, he creates more chances (key passes), and he is losing the ball less than McKennie (dispossessed per match; bad ball control stats). McKennie covers more distance, intercepts more passes and wins more aerials. They are identical or almost identical in the percentage of successful passes, in tackles per match, in dribbling and in blocked shots.
Why is the impression so different? Because we expected more from Ramsey and less from McKennie. But if one is having a bad season, then so is the other one. If one is having a very good season, the same goes for the other guy.
Or are they both having a mediocre season, or at least a season not worthy of a scudetto winning team? Just like Arthur, Rabiot and Bentancur.