The reason some apps are not removed after you connect them is that you can connect more than one account. For example, you can connect multiple G-Drive accounts.

That said, it's definitely confusing in its current form, so thanks for highlighting it.

The apps you suggested are definitely within reach (except for maybe Signal). We don't integrate any CMS's yet, but I think it would be quite helpful, especially for folks who tend to interface with them a lot.