"Friendship is Magic"
it is that hard to understand? the show is primarily focused on friendship with it's ups and downs (though now that Twilight is the princess of Friendship, I wonder how many other things she has yet to learn)
Bringing a topic such as sexuality is waaaaaay to much, and in fact not explored in pretty much every kids show. Fine, the heart and hooves day episode was focused on hooking up Big Mac and Cherilee, but straight relationships are so mainstream and common that the part of sexuality even if it's there, it is so implicit and subtle that it's actually not even 1% the focus of the episode.
So no, that's a terrible idea, too polemic and really, has nothing to do with the show.