(This is under the mindset that CN is still primarily targeted towards children, despite all the sjw pandering they've been doing lately)
The animation in the opening was okay, it felt a bit more genuine (interesting too) than the animation for the rest of the show.
The show doesn't really mention who any of the characters are or where they come from, they just appear and the viewer is expected to know who said character is. I wouldn't have a problem with this but as it's a cartoon meant for young children I feel as though just plopping random characters into an episode with little to no context is an awful idea for generating interest in said character. I get that CN is also marketing towards the demographic that watched the original show as children, which is fine and all but ideologies sjw-ism change all the time and if CN can't get it's younger viewers to connect to these characters then this show has no future if/when they accidentally piss off older viewers for doing something minor.
It's already dated, not just with meme's, and it's not just CN that's doing this either, it's Nickelodeon too. I've noticed this in the new Fairly OddParents (yes, I watched a few episodes of that a while back, it too was meh), both companies have overused the cellphone's (good god the first new fop episode, they mentioned selfies and duck faces so many goddamn times) I don't know if they're trying to compete for the most pop culture or what. Thing is though, do kids really even see those old meme's as a joke? will they even find it funny? If it's just a few pop culture references it would be fine, but if that's the majority of the jokes then there's a problem. There was twerking in the 4th episode of ppg and you have to wonder, do the people behind these shows know shit like this isn't taken seriously?