You can go ahead and send that open letter, but why not just fork it and go ahead and add the things you want until he accepts it? Adding contributions to the code and then telling him, "Hey, I added a bunch of things, fixed a bunch of bugs, etc. Can you give me push access?" is better than "Hey, you haven't been putting in much work into this project. Why don't you let other people work on this?". Who should he give access to? Why?
Good point! This letter was written after I've done much of that. Unfortunately, nothing has been done yet. But that's definitely the attitude that one should take (unfortunately, it's just deteriorated over time).
The reason I sent this email (and others) to Tom is because it seems like he's lost interest in the project - which is totally fine! As it's an insanely popular project, however, (one which the public has not forgotten about, certainly), I have an intense desire to push it forward and see it become all that it can be!
Give reasons. Not requests.