I seriously don’t see how The Phantom Menace is more watchable than Revenge of the Sith. Nothing happens in TPM that we care about; and Jar Jar and TPM-Anakin’s acting are not more watchable than ROTS-Anakin’s acting.
It depends greatly on our own point of view. If you’re looking at it from the perspective of the overall story of the saga, sure it’s fairly superfluous. But taken in isolation, [TPM]'s a grand, impressive, and weird sci-fi movie that just happens to take place in the Star Wars universe where ROTS tries so much to tie into the OT that it can’t help but be lessened by the comparison.
TPM is better in isolation than ROTS is in isolation because ROTS tries to tie into the OT…?
They’re called Episodes I and III. They’re not in isolation. They, on purpose, are supposed to tie into the OT.
Comparing Episode I in isolation is not the same thing as taking Rogue One in isolation because it’s not supposed to be a standalone film. As such, isolation ought not to be the only metric used. Even if TPM can subjectively be considered a better film by some, it’s definitely not a better prequel.