It is what it is. Little late to be complaining about it, when it happened all the way back in Rainbow Rocks.
I think it makes sense for Pinkie. She operates on her own rules. And her sister still has a rock for a pet. If they show the other sisters, they better have objects as pets too.
They might be trying to keep things reasonably realistic. An alligator is not the most practical pet in the world… and you wouldn’t be bringing it to playdates.
I hear the DVD release for the specials have much, MUCH brighter colors than the Teletoon or Discovery Family airings… Some are saying that it’s a little TOO bright on the DVD…