The CMC weren't even originally going to be in the show, they were supposed to star in their own spin-off series per Lauren Faust's wishes, but Hasbro shot the idea down in favor of the CMC appearing in the show. Now, eight seasons (soon going on to nine) later that decision seems to have been a wise one. In fact, I'd say the CMC have for the most part gotten off better compared to the mane six and Spike, though there has definitely been an issue of the show not knowing what exactly it wants to