Pyra/Mythra are what I would call the improved execution of formerly flawed concepts.
As far as general inclusion, I don't have much to say, Xenoblade's fairly popular, and they made sense to get in. The more telling thing about their overall showcase was that they were a Byleth style reveal done far better. Obviously there are differences in context, with FE having far more characters in and there being no real expectation or major rumors prior to the February 2021 Direct like there had been a year previous. However, not only was the trailer generally better (albeit somewhat obvious it was probably Smash and not XC2 DLC giving the timing), the general scenario was much more favorable, being in the first general direct in a very long time and basically guaranteed to have something to interest you even if you were indifferent to their inclusion. Essentially a lot of potential backlash from some Western fans was greatly mitigated by how they were shown off, and thus the overall reception was pretty positive.
As far as fighters themselves, to be perfectly frank I'd say that Pyra/Mythra are my favorite transformation set in the history of the series. My general issue with the likes of Samus/Zero Suit, Zelda/Sheik, & the Pokémon Trainer was a tendency to favor one particular part over the other/s, to the point where playing as the complete package never really that satisfying. The great success of the Xenoblade duo is that both are really enjoyable to play, and I rarely ever run into a situation of feeling like one is carrying the other in terms of either fun or effectiveness. Even as someone who's never touched the series, I'm grateful for their inclusion for finally making a long time Smash mechanic live up to its potential.
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, if it wasn't clear enough.
