Twi did pretty much squeeze the rest out of two-parters before long, yes. In the end they are only a small part of the show, though - but an importamt one.
Half the two parters just become the Twilight show. Princess Twilight was probably the worst, where most of the other characters just… vanished, and Twilight didn’t do anything particularly special (the only action she took that facilitated the conclusion was rescuing Discord). Crystal Empire was also annoying for the sheer amount of Twilight dick sucking, despite the fact that as pointed out later on Spike was actually more useful.
Most of the others aren’t quite so bad, but there is a lot of “Twilight, please stop having an existential crisis and weeping in a corner. Since we’ve all become strangely useless and passive in order for this plot to work, we can only win by the power of your incredible awesomeness. Have I mentioned how you’re a princess, best pony, and a very fetching purple color?”
Repeat until she starts to glow, the current bad guy’s face melts off, and everyone gathers round to congratulate her like she was the only one that mattered.
Starlight’s one two parter as the hero on the other hand has her as part of an ensemble, most of which have no strong opinions about her either way, and actually have Thorax doing the glowy thing and melting faces. Starlight’s screentime is about on par with Trixie, who also provides the majority of raw competence and really gets about the same amount of character development.
@Myoozik
@Philweasel
I don’t know, I’ve always heard that strong power abilities, approval rating in universe, having no visible flaws and overtaking the plot most of the time was what makes a Mary Sue. Regardless, I was never a fan of that term since it can get misused to mean anything like character one doesn’t like and such.
Help fund the $15 daily operational cost of Derpibooru - support us financially!