7. The Flash's final season was a complete misfire
With the unjust cancellations of Batwoman and DC's Legends of Tomorrow, it was up to The Flash to bring an end to the Arrowverse. It was fitting, really, because the Arrowverse's second show had gone on to eclipse even its predecessor, achieving record-breaking levels of success for The CW and becoming one of the biggest shows on television around the world. Unfortunately, its final season was a miss.
The show had been struggling in recent seasons anyway, but a 13-episode final season should have given it a chance to concoct a coherent straightforward storyline to bring everything to a close. That wasn't what happened, as the final season instead opted to repeat the same mistakes that recent seasons had made, resulting in a heap of wasted time and momentum.
The "graphic novel" format, which splits the season into two storylines and a three-episode interlude (a.k.a. filler episodes), worked in longer seasons, but in a shortened season tasked with wrapping up The Flash, it was a huge mistake. There wasn't enough time for either of the two storylines to find their footing and that made both of them come off as incredibly half-baked. That was especially the case with the "A New World" saga, because it started off very well and then wasted the little time that it had going through the motions and placing the focus on the lackluster new characters that fans just didn't care about.
All the mistakes of the previous two or three seasons were repeated, the fans weren't listened to, and one of TV's biggest titans ended up bowing out with a whimper, producing only two or three good episodes in a season that completely misunderstood the assignment.