Contains spoilers from The Flash Season 5, Episode 22.
The Flash's fifth season has had more than its fair share of highs and lows. While it has been a vast improvement over the lacklustre mess that Season 4 was, featuring a compelling and well-mapped out narrative, it has suffered from episode-to-episode due to its weak villains (Cicada and "She-cada").
That being said, it all came together nicely in this week's season finale, which saw Team Flash grapple with whether or not they should destroy Cicada's dagger, knowing the consequences that such an act could have on the timeline. As they found themselves in this dilemma, the Reverse-Flash himself, Eobard Thawne, was moments away from execution in 2049, waiting patiently for the power-dampening dagger to be erased from history, and when his prophecy came to pass, the timeline was changed forever.
'Legacy' effectively relegated the Cicada arc to the subplot in order to place the spotlight on the more interesting story revolving around Reverse-Flash's master plan. In doing so, it allowed the divisive season to end on a high and produced one of the show's strongest season finales.