Whilst that may be true I personally wouldn't want too many people working on my project. It would bring about more issues as more people means more ideas which means more differences in opinion which means more conflict.
I think the best thing to do at the moment is to be patient and see how things pan out. Toby, Franz and Daniel are all doing amazing jobs getting things on track and ensuring things are being done whilst at the same time concentrating on real life matters, commitments, etc. Remember, this isn't a company or other corporate entity. These are individuals who are doing this part-time.
Anyone can assist right now by helping out with fixing bugs and helping out with extensions of course. It's just a matter of time before we can have a finished product that is stable. In the meantime, you can definitely be confident about installing your own instances of Flarum right now. Just go easy on extensions and modifying any code to prevent issues upgrading/updating for future releases.