If it's an experimental module, then it can surely wait for the next release; after all, nobody should be relying on code that's explicitly marked experimental.
Bug fix windows are for bug fix. If it’s not a bug fix, it goes in the next version. That’s how the kernel release cycle works. It’s not very complicated.
If it’s so unstable that it urgently needs new features shipped regularly, I think it’s entirely legitimate that it has to live out of tree until it’s actually stable enough.