Installed plugins that fail to load should me noticed in the Administration > Manage plugins page
On a system running 16.11.04.000 I tried several times importing the KitchenSink plugin, but it would not show up. All the files were imported correctly. After some research I found that the KitchenSink uses C4::Branch that is no longer in the version I was using. After commenting out the C4::Branch the plugin appeared. Note: there are some other issues that prevent KitchenSink from running completely.
I agree there should be some sort of Error message that the plugin was imported with errors.