It's given me a broader vocabulary to describe what's going on, and a selection of tips, tricks and patterns. I can say what's good about a piece of writing I like, but I can't fit it into an overarching coherent theory.

My experience is that writing isn't a field that would have an overarching coherent theory - instead it only has an endless selection of "tips, tricks and patterns", as you put it. Becoming a better writer is just about constantly expanding your toolkit of tricks, by being explicitly told tricks, taking apart other writers' work to discover theirs, and experimenting with inventing new ones. Read a lot and write a lot.

(Stein on Writing is my own favorite collection of tricks, covering both fiction and non-fiction writing.)