Speaking as a collaborator of over ten years with multiple books on the shelf, let me give you some advice.
You'd probably be better with a critique partner or group than a collaborator. See, all writers have very intense feelings about their work and about three things you said in your post would initially be fine, but would eventually lead to problems.
1) See, I have no doubts about the story itself. This is problem #1. If you want the book to be the best it can be, and recognize you have SOME problems with writing (narrative, as you stated) then there are problems with the story. Changing narrative necessarily changes the story because what often happens is that realistic dialogue and movements changes the very nature of the character. It gives them personality traits you hadn't considered and sometimes those personality traits--that spoke those wonderful words that you might ADORE--won't perform the plot movements you've given them. So, they need to change. And if you have no doubts about the story, then those changes will grate on you. Trust me on that part...
2) I'd want someone who's good at phrasing things but who'd be willing to defer creative control to me. This is why you might consider a CP instead. The "defer creative control" part will start to grate on the other guy at about chapter 10. Basically, what you're saying here is that you don't plan to respect the other writer's vision for the book, in making that book the best it can be. Now, that's not a slam against you. MOST writers can't work well with a co-author. The only way it works for my partner and I is that we
TRULY BELIEVE, with all our heart, that the other person has good intentions toward the book and that their writing skill is equal in every way. However, one thing that does help is that we use a "lead author/secondary author" partnership, where the person who originally wrote the book (and we trade off, every other book) gets final say in what's written. Then if feelings are minorly hurt by not taking a suggestion, it's soothed by the knowledge that on the next book, the other person leads. But very seldom do we not take the suggestions anymore. It just works better.
3) I have a very strong idea on what I want so chances are I wouldn't go along with too many changes. This goes in with that "respecting the other writer's vision." Sometimes we get so attached to our story that we can't see the faults. Unless you're willing to let go of your ideas to see the potential that lies in your concept, it's difficult to get a book shelf-ready. If you're not willing to change the book at the entry level stages, it'll be that much harder to take the advice of an editor at a major house. They'll be making PLENTY of changes once you've been accepted. But listening to ideas is a skill, just like writing. And it's better to learn with someone you trust. It'll make it that much easier.
Then, who shows up on the cover when it's time to publish? If you collaborate, the other person will probably expect to share the limelight and the fame. Otherwise, they might as well be a ghostwriter.
Our partnership started pretty much like you stated here. My co-author is a wonderful writer, but had some faults, and the same with me. I was GREAT at action and sex scenes, where she was AMAZING with creating three-dimensional characters that people really get attached to. Combined, we were able to take an okay, but somewhat lackluster book and make it
awesome. And, I'm a business-minded person who has no fear of rejection, where she is an introvert who is easily bruised by criticism. So, we decided that I would be the business side and would make edits, while she would be the person in "creative control" of the books. Except . . . it didn't work out that way. As we both grew as writers, she started to be able to write action and romance (through sheer repetition) while I was forced to learn how to create characters because we were under contract for multiple books and it was hard for both of us to work on both of them at the same time.
Too, there was the problem with promotion. She was so much of an introvert that nobody knew she existed. We started out like "Sears & Roebuck" with me Sears and her Roebuck. (Who goes to a "Roebuck" store, after all?) But after the second book signing where her name didn't make the announcement and there was only ONE seat at the table, we realized that introvert (no matter how much I publicized her name) didn't fly. Readers have to know the author really exists, so she had to come out of the woodwork. And, in so doing, she realized she didn't mind the fanfare as much as she thought she would.
So, now we're Black & Decker. Nobody buys a "Black" saw, nor a "Decker" sander. We're equals.
Ultimately, you have to really think about what you want. If you want the book to be AWESOME, then you need to let go and give up some of the control. But if you don't think you can do equals--in every way--then you might well consider either taking classes to strengthen your narrative skills, or seek out a critique partner (one whose opinion you can dismiss without offending) or a critique group, where you can get ideas from a variety of people. But if you expect a person to actually put their hand to the task of writing the book, then you need to think about what that person will get in return for their efforts.
Good luck, whichever way you go.
