As much as I like to write too, If I was going to collab with a writer it's because I love the story they want to tell and want to see it exist in the world as a comic.
I kind of see it as like: if you were going to a studio to get your TV or Movie screenplay considered wouldn't you have a complete story (Even as a robust pitch) to show the people who would be lending you their skills and time to produce the story in that given medium? You have to demonstrate you know your story inside and out and sell them on why the story should be made. So first step: tell me a good story.
For me it's not about the profit I might get but more about the story that is to be created.
Personally I would want a detailed outline and/or complete script before I considered a writer to be truly serious (especially if they can't point me to written works they have already finished). This speaks to the reliability and commitment of the writer to their craft.
Since I've gotten the chance to work on nearly every stage of the comic-making pipeline in collaboration with others (I'm a freelance editor, line artist, flats artist, and Renderer/Colorist right now)-- a story is more easily able to be drawn and produced if the story/script is clear, specific and well-structured.
The best writers are willing to give stick figure story boards if needed or good reference images they found, and have a decent grasp visual storytelling so they can help guide the artist to their vision at an editorial level.
Yes this means you should study the basics of camera angles, lighting, drawing (figures, body language), acting, sequential storytelling, etc/anything else pertinent to your story. And more important than anything learn to format screenplay style. Comics are not prose and don't do well in a very novel-style format. The story can be big but it has to be told effectively.
You don't have to build the skills to do it yourself necessarily but you do need to understand it to communicate with the artist. It will help the writer be specific and avoid miscommunication. Learn the art and comic jargon.
Trust me, a true collaboration means the writer is able to clearly express what they see to the artist who has the skills necessary to translate that into the page.
Side note: Summary
There is a misconception among creatives that you need complete freedom to express yourself. Instead ultimate freedom often has a freezing effect on the creative process. Consider the blank canvas/page dilemma when you have no inkling of what you want to say.
In reality, and especially from my experience, Creative Restrictions unleash the greatest creativity. Every time. Innovation thrives with limited resources cause you have to 'get creative' then. That's why favorite topics or genres or just anything you love or hate needs to be there to fuel your tank.
That's why I'd want to only put in the effort to bring to life a story from writers that have a track record of finished writings. I have finished one major comic and am part of so many more right now so I know I'm reliable. I would need the writer to be so as well.
That's said, If the writer needed editorial help, I'd probably be able to lend a hand if the early outline/ Pitch was very compelling to me. But I would only help them tell the best story they want to tell, not dip my fingers in to put my own spin on the story. If I want to tell a story my way, I'd just go and do that xD;;
I know we don't want to go into an art vs writing thing but I just want to say that at the core they are one in the same. Comics are about telling a visually sequential story. Writing is not words on a page, it's the structure of the storytelling.
Writers might 'write' using words in a script and the artist 'writes' with how they compose and pace the art panels and dialogue bubbles(which are integral to the art composition). Both ultimately have to tell a compelling story. They both have the same goal but different complementary skills.
The writers skills must amount to communicating clearly what they see in their heads. And the artist's skills must amount to receiving that communication and finding the best way to show that story visually. That's the measure of effort I would gauge ---not who's spending more time or effort doing this or that.
A writer who is intellectually lazy and disguises "I'm not actually going to put in the effort of learning even the basics of visual storytelling so I can be an effective collaborator on this project" as "draw it however you like, you have the freedom, I've written the story now it's your turn"--- is one I will avoid.
Artist need feedback. Even when they think they don't. They do. The writer side should learn to be a decent editor--that's how they can best get involved in the art side without stepping on the artists toes.
If it's a damn good story, the surface-level efforts don't matter as much cause you're both motivated to see the story come to being.
Collaboration also means taking care of each other on a human level and making sure both sides are working at a reasonable and accountable pace.