In Lessons from a Lifetime of Writing, David Morrell says the following about characters: "Which are harder to write: types or multidimensional characters? I suggest types are harder because the narratives in which they appear impose limitations that make it more difficult to be creative."
Let me say, clearly, that I absolutely disagree with this. Let me also say that a writer in my writing group who publishes at a much higher level than I generally agreed with Morrell, and that I don't believe even creating a good character "type" is easy.
What evidence do I have to support my view? I will readily admit that it is anecdotal and/or non-scientific, but here's what I see.
1). There are more writers publishing and making a decent living out of writing types than multidimensional characters. This is despite the fact that readers in most genres will accept a multidimensional character even if they don't require one. I can enjoy a good private eye novel with a character who is very much the standard hard-boiled detective, but I don't mind if the writer has added something extra. So why don't more writers add that something extra? I suggest that it's a lot harder to do so.
2). Here's an analogy from painting. Character Types have certain standard characteristics that they need to exhibit. If you've read a lot in a genre you pretty soon pick these characteristics out. Then it's at least partly a matter of inserting these characteristics into your own work. I know that's not easy, but this can be a little more like a "paint by numbers" work than a completely free-hand painting. I couldn't paint a decent free-hand painting to save my life, but I can follow specific guidelines I'm given. It may not look terribly pretty but it will be servicable.
3). I've tried writing types and I've tried multidimensional characters in my own work. I find types immensely easier to work with. This is not necessarily to say that my "types" were well done, but I did get paid for them. I always try in my own work to give my types a little something extra, but I don't know if I've ever written a fully multidimensional character. I think the closest I've come is Kargen from Cold in the Light, and he isn't even human.
Developing good characters is never easy, of course. And this goes for types as well as multidimensional characters. I know people who have read extensively since they were young in a genre that they want to write in, and yet they don't seem to quite capture the essence of the character or the genre and their work remains largely unpublished. But I don't believe these folks could write a multidimensional character either.
Maybe I should do a little test of my own. For example, I've never written a hard-boiled detective character. Could I pull it off? I don't know, but I'm reading a little Raymond Chandler now and I'll see if I get the itch. I'll let you know what happens.