One of my favorite things about Friendship Is Magic is the near-total lack of romantic relationships. There are very few canonical pairs, and except for Shining Armor and Cadance, they’re all far in the background–pretty much just the Cakes and the Mane Six’s parents.
There are two things I like about this. One is purely personal: I’m sick of romantic subplots getting shoved into everything, and glad to see something that doesn’t have them for once. The other is more for others’ sake: it creates a space into which viewers so inclined can insert interpretations of the characters’ sexuality and romantic behavior that might not be supported by the text.
It makes shipping easier, in other words.
Now, I personally am not a big fan of shipping; as I said, I’m sick of romantic subplots, so I’m not going to make up my own. That said, shipping does serve a useful function in that it allows people whose sexual interests might be underrepresented or even taboo to find something for themselves in mass media. For example, there is no way in hell Lyra/Bon-Bon could be depicted as a canonical pairing in a children’s show in 2013; Western culture has come a long way in combating its rampant homophobia in the past few years, but nonetheless the mere depiction of a same-sex couple is still considered more risque than a heterosexual couple.
By not having much in the way of onscreen romance, the show allows everything from my own “all ponies are entirely asexual, but a small percentage are romantic asexuals” to “everypony is having off-camera lesbian orgies multiple times a day.” So I can happily watch knowing that I’ll never be contradicted by the show, but so can someone who ships Big Mac/Cranky Doodle or Fluttershy/Crysalis or Angel/Spike. (Do people ship that last one? If so, is it called BuffyShipping or VampireShipping or something like that? Because that’d amuse me greatly. Still wouldn’t touch those fics with a ten-foot pole, though.)