Hi,
I am a developer of mozlz4-edit , dictionary configurer and other small addons. You can see my profile page on https://addons.mozilla.org/firefox/user/12619594/
Yesterday I received an email from Mozilla that tell me that my addon was blocked. Reasons in which it was happened are:
1) I allowed eval() function in manifest.json and I need delete the permission or persuade a Mozilla reviewer that it is necessary. ( I didn't used eval in code, it was just a useless permission)
2) I need an instruction how to build my code and I need to upload an archive with the addon source code.
Firstly, I want to answer on second issue reason about how to build my code. Well, the addon that was blocked is an open source addon, I uploaded an archive with the source code early, the source code is available on github and there is instruction how to build it.
Secondly, There is no such thing as a dangerous addon permission because there are a lot of ways to make a harm with any of addon permissions. Moreover, "evil" permissions are needed to run addons with some frameworks. For example Angular (js framework) needs some special values in content_security_policy and code just don't work without it.
As you understand I don't work in Mozilla.

P.S. The addon that was blocked is shadow dom opener. It "opens" closed Shadow DOM elements on page because such elements are not available for JavaScript at all. It means that user scripts and JavaScript plugins won't work with "closed" Shadow DOM elements.