The qualms I have with the series are mostly just that as the episode orders got overwhelmingly large, the bar for which episode pitches got greenlit lowered, and who was allowed to write them, and it led to a lot of filler in the latter half of the show. So it's not like I think the series is beyond critique. Im gonna download it and sequester the low quality episodes into their own folder so that when I eventually rewatch it I can stick to the good stuff, of which there was plenty all the way through to the end. But the people complaining that Finn became more passive and emotional, or that there was a gay couple... idk it feels more like you're taking your cultural frustrations out on it in a way that's just silly.
If I had it my way I would've liked to see one last episode after the events of the finale where it's just Finn and Jake hanging out and going on an adventure, kind of on the same note that Calvin and Hobbes ended, but more as like a denouement, because the finale worked perfect as a climax to the series imo.