Following on with what The Big Peat said, I can sort of make a case that all writing is technical. Or, if you prefer, it's all imaginative. I'm not entirely sure what the OP envisions belongs under the heading of Technical, but I would argue (nearly said "I would imagine") that it entails more than spelling and grammar.
Constructing a believable character arc, ensuring continuity, getting proper flow between chapters, pacing (both over the book and within scenes), scene structure, all these and more are technical, but they all require imagination to get them right. A craftsman doesn't create a beautiful work on imagination alone; it requires knowing the craft.
As for why we tend to talk here less about imagination than about other topics is, as others have said, because there's so little to talk about when it comes to imagination. The word itself is hopelessly fuzzy, though if we pare it back to its root, it becomes sharper. We can talk about imagery, how we go about creating a vivid image, whether within a scene or within a single phrase. But when the word is used as shorthand for "coming up with cool ideas and ways of using cool ideas," or again as shorthand for passion about life and about writing, then it's much harder to have a conversation much beyond personal anecdotes. Not to belittle any of that, but it's not the sort of thing to spark long, argumentative threads with sources cited.
Constructing a believable character arc, ensuring continuity, getting proper flow between chapters, pacing (both over the book and within scenes), scene structure, all these and more are technical, but they all require imagination to get them right. A craftsman doesn't create a beautiful work on imagination alone; it requires knowing the craft.
As for why we tend to talk here less about imagination than about other topics is, as others have said, because there's so little to talk about when it comes to imagination. The word itself is hopelessly fuzzy, though if we pare it back to its root, it becomes sharper. We can talk about imagery, how we go about creating a vivid image, whether within a scene or within a single phrase. But when the word is used as shorthand for "coming up with cool ideas and ways of using cool ideas," or again as shorthand for passion about life and about writing, then it's much harder to have a conversation much beyond personal anecdotes. Not to belittle any of that, but it's not the sort of thing to spark long, argumentative threads with sources cited.