Firstly congratulations on the program concept.
But I have some observations.
A) In countries whose main language is the same as in latin america where the language is Spanish, the plugin does not work.
You are unable to setup in: setting >> general >> Site Language
Because many countries you will not find the specific .mo files. Than you is unable to setup the correct country and flag. Try to do es_CH and es_AR.
B) Other point the hreflang is today a extremely important factor in google seo of international projects. There are some way to setup that?
C) Is possible to create a customized switcher?