This Plugin adds several enhancements to the WP-Link Modal inside the TinyMCE and gives you the possibility to disable the wp inline link tool.

In this first version you are able to:

1. Add custom classes to your links directly inside the TinyMCE WPLink modal box
2. Enable/Disable the Inline Linking from WP 4.5+
3. Add a rel="nofollow" to your links
4. Add a title-Tag to your links

If you have ideas for improvements, feel free to dive into the code:
https://github.com/nico-martin/AdvancedWPLink/