Unless Amazon has substantially changed it's outlook on the Fire TV, Kodi is a disappointment. It's buried in a submenu and requires side-loading, and you have to mess with the device to get it to load as the homescreen or be surfaced on the main app launcher.
Simple step by step tutorial allows you to load Kodi from FireTV through any app icon.
I'm getting a database error when I click that link, but if it's anything beyond "open store app, download app, go to home screen, run app", it's a third-class citizen (considering that Netflix et al are second-class citizens on the Fire TV).
The "easy and quick to set up" option is ten steps, and that's just to get the app on the home screen (rather than to replace the home screen). In what world is that not a third-class option?
I don't think of these things in terms 'classes'... the side loading + icon launching thing is a hack but easy to do and works great. Knowing Apple I doubt such a thing would be possible.