The broken by design thing is something that's always bothered me. I posted a draft of our company's Privacy Policy to github a while back as an experiment.
Having faced the same situation in the past, I encourage you to simply release it. No need to spend months upon months improving the backend while no one is using the damn thing.
How long has the refactor been on your mind? Has it been at least a month or two? Has your mental picture of the rebuild been consistent, or does it change week-to-week?
Here's my advice to get you going: Write down your general refactor plan in detail. Next, create a todo list / timeline that gets you to production deployment as quickly as possible based on your current codebase. Focus on other things a bit. Launch, marketing, etc.
Once this thing has been out in the wild for a bit, reassess that refactoring plan you wrote down and see if it still makes sense based on your application's performance - both as a product, and as a piece of software.
To my way of thinking, this is exactly the kind of stuff that makes mobile computing so exciting: Choice and control.
Imagine when folks are able to be just as discerning when they are shopping for clothes (was this made in a sweat shop? is it american-made?) or grocery shopping (were these chickens treated humanly?).
