>>150012074
to be honest i'd say early-mid season 2 is tied with it. That was where the revamped art style looked the best.
That being said there are some things about season 1's world that I don't understand why they got rid of. The 2D clouds during the day and the anaglyph cartoon stars at night were cool. I remember early season 2 was trying to do a thing where they would blend the 2d clouds in with the real life ones (pic related) but that got dropped pretty fast.