Expectations were mixed for "Triple Threat" on first watch. While Thorax is not one of my favourite characters on 'My Little Pony: Friendship is Magic' he was a strong character in Season 6's "The Times They are a Changeling". The same goes for Ember in "Gauntlet of Fire" from the same season. At the same time, Spike with a few exceptions doesn't have a good track record when it comes to episodes around him, but there was hope as his characterisation improved massively in Season 6 and one of not many consistently good things about that season.
"Triple Threat" left me somewhat mixed on first watch, though actually better than expected, liked Thorax and Ember but Spike didn't add much. On rewatch, it fared better. It does not sound anything exceptional or special on paper in terms of concept but there are numerous examples of concepts and story ideas in film and television that sound quite basic and unexceptional yet are executed much more compellingly and easier to invest in than expected. "Triple Threat" fits in this category.
Am going to start with the good. The animation is vibrant and meticulously detail. Some don't like Thorax's character design, it has never bothered me actually and the animators have always done well with the little animation details to him. The music is dynamic while also with an atmosphere and groove. The writing flows well and never comes over as too serious or gimmicky. The story, though not flawless by all means, generally has a nice energy, if not a fast and furious one, and charm. Lyra has a nice cameo with one of the episode's better lines.
Really liked the character interaction between Thorax and Ember, which was cleverly witty and works well. Was worried at first with them being such polar opposites and with the whole scenario being set around not trying to have them together, but it was very surprising at how by the end of the episode how sympathetically done their chemistry is. They also as characters elevate "Triple Threat" to a higher level. Thorax is again a sympathetic character without the episode not going too far on it that he becomes dull. Ember has a very forceful and even personality that could have been too brutish if taken too far, but actually she doesn't become that or too mean.
Where "Triple Threat" is less good is with Spike, in another scenario where his well intended attempts to fix a problem actually gets worse which is exactly predictably what happens. Also found him on the bland side as a result of the episode trying not to exaggerate any negative traits (which is what tends to happen in the Spike-centric episodes) and for an episode centered around him he felt almost unnecessary.
It is not just Spike though that is a problem, yes every episode of heavily flawed 'My Little Pony: Friendship is Magic' are not hampered by just one thing. Did feel that at times the conflict was forced and predictable. Also that the ending was too abrupt.
Summing up, not bad at all and better than expected but far from being one of Season 7's best (or worst). 7/10.
