It wasn't that it was bad, in concept, but it was entirely rushed
Hirsch's plan was originally 3 seasons with a TV movie to act as the finale, and this was still the plan as Season 2 began pre-production
We don't know all the details, but around the beginning Season 2 , and most likely while they in pre-production on the second-half of the season, Hirsch announced it would be the last season because 'It was too daunting to be the show-runner' but it's been rumored he's just lazy and that he would throw tantrums when Disney would force him to change things; specifically to keep it more on acceptable for the channel and Hirsch didn't like people controlling 'his' show, despite him making it for Disney.
They had to cram a whole season and a movie into the span of half a season, so the pacing was terrible and ideas that were there since the beginning were just thrown out because they didn't have time to set them up. The worst part is we still got filler during that time because, according to Hirsch, 'The audience needs some breaks from the plot so they're not overwhelmed'
Disney apparently asked for the series to continue past Hirsch's initial 3 seasons, but he refused; and you can't really continue the show when half the cast's VA refuses to record new material.
The ideas of the finale worked fine, and even what didn't probably could have been better with more time to fix it up. Hirsch is a hack and ruined his own show.>>115820489
Having not seen GOT, it's Star's because that ending came out of nowhere and didn't align with anything the show said up to that point. IIRC Nefcy said that she was expecting a 5th season, but found out she wasn't during season 4's productions, and that she wouldn't have wasted half the season on shipping if she had known that. I'm sure Glossaryck being nearly written out of the show entirely because of Jeffrey Tambor's scandal didn't help much the planned plot either, so they had to rework some major things.