The point of design patterns is not just to solve particular problems, but to solve larger problems by putting together solutions to smaller problems in a coher

The point of design patterns is not just to solve particular problems, but to solve larger problems by putting together solutions to smaller problems in a coherent way. Category theory is just the right language for talking about putting things together, even if the individual pieces you want to put together are less sophisticated than, say, a cartesian closed category or a universal property. So I disagree, I think the title is right. If you don't go as far as category then you've stopped short of the biggest pay-off.