I thought Super Paper Mario was kind of a mess in almost every aspect but soundtrack and characters/story.
Level design was boring at best or annoying at worst, the visual design of random shapes was utterly unappealing, and the flipping mechanic meant there was no point to playing any characters besides Mario. I consider it a huge, huge step down from the first two games which are masterpieces. But I've accepted that those style of games are probably dead unless Intelligent Systems and Nintendo suddenly get their act together.
Level design was boring at best or annoying at worst, the visual design of random shapes was utterly unappealing, and the flipping mechanic meant there was no point to playing any characters besides Mario. I consider it a huge, huge step down from the first two games which are masterpieces. But I've accepted that those style of games are probably dead unless Intelligent Systems and Nintendo suddenly get their act together.