If Ramsey is not capable of delivering the same engine as Matuidi, then the coach sets up the team differently. For Example he plays Ramsey - Pjanic - Can and instructs the latter two to hold the midfield while Ramsey can move forward more freely. I think that would work just fine.
Bottom line is that Ramsey seems like a much more productive player going forward and that alone should justify playing him. If he's injury prone - no problem, play Matuidi with a little different setup