I understand that this series has a habit of avoiding the term king or queen outside of villains, but why was he only referred to as "the new ruler of the Changeling Hive"? I mean, if there was a 10 second bit where Spike was going to refer to Thorax by title only for Thorax to brush it off, that'd be one thing, but nothing. He's a visiting head of state for goodness sake! And we know that visiting heads of state get referred to by title, as Cadance and Shining Armor have gotten that treatment.

I mean, it's not Season 1 anymore. We'd understand a miscellaneous nobleman being called a Duke, and we'd understand why the female monarch being called a Queen*. It's not that hard, people.

*I actually prefer her being a princess, as it showed humility and regret for banishing the other half of the Diarchy.

5911029 We have to acknowledge that the Changeling kingdom is still in a change in the dynasty and it might be restructured as something else, maybe even something like the Crystal Empire (an autonomous principality) and as such holding off on the titles. Also the very notion of someone ruling other that Chrysalis is still something the Changelings are still getting used to.

5911029 maybe he himself is unsure or uncomfortable with an actual title, so for now, he's just the 'Ruler of the Changelings.'

5911029 Maybe he hasn't officially been corinated/crowned yet? Remember, Princess Celestia was the one who declared him the new leader of the changelings, not the changelings themselves. So the changelings may still be in debate about whether or not Thorax should be their king, or if he should even be their leader. For us he'll probably be considered king until canon says otherwise.