Season 8 still leaves a lingering, bad taste.
Castle is the kind of show that made its mark in a time and place when television was changing dramatically. When it debuted in 2009, network TV was still king, and getting noticed as a new show was not easy.
However, by the time Castle went off the air in 2016, the television landscape had changed forever. Today, network and cable TV may not have the same appeal, but Castle remains one of the most popular and successful shows of the early 21st century.
Be that as it may, for many fans, the finale of Castle was hard to take. Not only did the final season leave a horrible taste but it also failed to deliver a rewarding, satisfying conclusion. As such, fans continue to mourn the loss of this witty, amusing, heartfelt TV show that had so much potential.
Fans still view Castle wedding as a missed opportunity
Castle became one of the most popular TV dramas of the early 2000s. The on-screen chemistry between Nathan Fillion and Stana Katic was explosive and really got fans invested in the characters of Kate Beckett and Richard Castle.
Unfortunately, things started to go sour around Season 6 (although there were signs that Castle was going in the wrong direction long before that). By then, it was clear that Rick and Kate were destined to be together.
However, what the audience got was a chaotic, rushed wedding (S6, E23: "For Better or Worse"). The season finale left diehard fans feeling dejected, considering everything seemed to be building up to this moment. And it only got worse from there.
Castle lost focus in Season 7 - 8
Castle spent the first 6 seasons trying to solve the murder of Kate Beckett's mother. The story dynamic was important because it was the entire motivation for Kate to become a detective. However, when it came time to investigate this mystery in Season 7, the entire show went off the rails.
Instead of pursuing the serial killer that a young Rick Rodgers stumbled upon in the woods, the show ignored him in favor of a convoluted narrative about Rick's strange disappearance. What's worse, Season 7 was lackluster, but nothing compared to Season 8, which prompted the show's producers to immediately cancel the entire series.
The audience has better alternatives for how Castle should have ended
There is no doubt that Season 8 was a disaster for Castle. There were several actors who had already signed contracts for a ninth season, but the final episodes were so bad that ABC canceled the show altogether.
Despite the bad news, it came as a relief to longtime fans. At first, Kate and Rick were likable and relatable. However, by Season 8, both characters felt like they had devolved into barely recognizable versions of themselves.