Okay, so here's my suggestions to help you work out some kinks I'm feeling.
What exactly is the plot of the story?
A lot of people like to know why they're partaking in a story. If we can gather a general idea of what will happen, we're usually more likely to engage in the story. There is nothing wrong with a loose plot, only it's not for everyone (such as myself, I find stories without plots or general directions to be unorganized and hard to really dive into -- but that's just me).
My advice is to really hone in on what you want this story to do. Is this just a free for all? Like in the Sims where there isn't really a purpose, other than to have fun. While figuring that out, you might think about the end result. What do you want the participants to take away from this story. How should they feel? What should they think? How will this help them?
Think about what makes you join roleplays. What do you like? What are you drooling over? What are some of things that make you cringe or shy away from an idea? What about those indifferent roleplays that don't make you feel anything -- why do they make you feel this way?
Sometimes too much ambiguity can be confusing.
I've been there, done that (and I've had someone rip my idea apart limb from limb). We all want to make all-encompassing stories that will meet a wide range of participants. But sometimes having too many options makes it too hard to manage. And it can also be super confusing.
My thought? Maybe cup down on the number of oddities and worlds to travel to. Rather than having people make up their own planet, god, races, etc. you give them three worlds to work with and then they can build characters off them them. If someone can and wants to go outside those preset ideas, then you can let them do so.
The reason I wouldn't join this is because it seems like I would invest a lot of time and for nothing (this isn't meant to sound harsh or rude, I just wanted to let you know my honest thoughts behind this). I love making characters, worlds, races and such up. I do not like when a roleplay only lasts for a week. Investing much time and effort into something that is loosely designed is a big "no-no" for me. Again, I would offer setting up some boundaries and stuff. There is nothing wrong with making up five worlds and then having people design characters after those worlds. And, again, for me, I want a plot -- something to work with. A direction and reason behind the game.
Let's dissect one of my less-involved games - S7Nera. It doesn't really have a setting as it changes from era to era. The ideas behind the story are comedy (that's another thing to think of -- what genres you want to fill) and adventure. The roleplay has a plot -- a loose plot but a plot nonetheless. Seven people are trying to save the world. It's a generic and vague plot, but everyone knows what there character(s) should be doing -- saving the world (or trying to destroy it).
Overall.
Overall, I think this is a cool idea. I love the creative freedom as well as the idea of making up your own gods. If you were to tie up some of the loose ends, I think people would be more likely to buy into the idea.
What you've done, though, is correct. You've made a brainstorm thread and you've asked for opinions. Those are both two big things -- and big things you actually did. So you're already ahead of the game. To further better yourself, I might glance over some of the more popular games on here and see what might have drawn people to the idea. Also read your own stuff over - in your head and out loud. Give it a quick overview. Like an elevator speech. If you only had 160ish words to describe this roleplay in, what would you say.
Again, you've got a good start. Now, you just have to decide where you want to go from there.
Well, I hope all of this helped. If you have any questions, feel free to ask. :) Oh, and good luck! :D
