Warning: The following contains SPOILERS for The Flash season 8.
A major problem with the story arc model of the modern Arrowverse was exposed by The Flash season 8, episode 16, «The Curious Case of Bartholomew Allen.» Most episodes of The Flash season 8 seemed bloated and drawn-out, thanks to the current policy of dividing each season into a series of self-contained stories. «The Curious Case of Bartholomew Allen» was an exception to this, largely focusing on a single story involving a new supervillain. This harkened back to the golden days of The Flash's earlier seasons, which featured season-long storylines made up of several stand-alone episodes.
This shift began with The Flash season 6, when current showrunner Eric Wallace took over. Wallace envisioned breaking each season up into a number of "graphic novels," with shorter, self-contained stories so as to avoid the arc fatigue many complained of with the previous seasons' year-long storylines centered around a single major Flash villain, like Savitar or Zoom. Unfortunately, the recent seasons seem to have overcorrected, now offering so many short stories among The Flash's ensemble that many of them seem to lack the depth and complexity of the earlier seasons' slow-boiling storylines.
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«The Curious Case of Bartholomew Allen» averted this problem by focusing most of its run-time on a single story concerning a mad scientist's quest for immortality. His use of a Gamma Absorption Array caused Barry Allen to start rapidly aging whenever he used his powers, requiring every free member of Team Flash to focus their efforts on corralling an increasingly erratic Flash, who was starting to descend into
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