No, but it's one of 'em. Objectively speaking, I'd say that Gravity Falls was probably the best cartoon of the decade.
Steven Universe is way up on the list, too. I'm going with Gravity Falls because on top of everything else, it had consistently excellent animation.
It might break the top ten. But remember that it's going up against shows like: -Steven Universe -Adventure Time -Gravity Falls -Young Justice -The Legend of Korra -Rick and Morty -Star vs the Forces of Evil
I think those 3 are more consistently good than MLP. MLP's quality varies wildly. For every Perfect Pear or Amending Fences, there's a Mysterious Mare-Do-Well or Spike at Your Service.
I wouldn't say that Steven Universe has been consistently as good as MLP. I found Steven to be so annoying in the first episode that I didn't continue the series until I started hearing how GOOD it got in later episodes. MLP started out strong, and has faced quite a few hiccups in episode quality since the second season. Gravity Falls, though. Started strong, just kept getting better, and left everyone wanting more. That was about as close to perfect as I've seen a cartoon get in a long time.
YES!!!!! Next question!!! SRSLY, though, in an age where many animators have figured out effective ways to inject deep and relevant meanings into children's programming, MLP does have some pretty stiff competition. MLP's messages are a little more on the surface since it's intended for a younger audience than something like Adventure Time or (from what I've heard) Steven Universe. Shows like these are much more than just noise and colors to shut your kids up for a few hours a day. If MLP isn't the best then it is definitely near the top of the leaderboard.