I think narrow diamond is easy to beat with wide diamond. Wide diamond can focus passing down both flanks while narrow diamond can only go through the middle where there are defenders and a DMC in the way. Of course it depends on tactics and quality though.

As a wide diamond manager myself, I tend to struggle against teams that pack out the midfield (such as a flat 5 or flat 4 with DMC). That said, being only level 2 I haven't struggled that much yet