Black Clover is one of the few anime in recent years to release on a weekly schedule continuously. While it has remained faithful to its source material -- with few fillers -- the anime adaptation has closed in on the manga's recent chapters, and its final episode will be airing on March 30th. The decision to end the series rather than inundate fans with unnecessary filler episodes shows an intent to remain consistent with the manga, which is still being released.
Though Black Clover's end may be unexpected, it doesn't mean the series won't return in the future. However, it does beg the question, should all anime be seasonal to allow the manga to maintain a lead on its adaptation. Long-running anime like Naruto, One Piece and Bleach used to follow a constant weekly release -- with no seasonal breaks. While this format still exists, releasing a set number of episodes has become the more common approach. So, should all anime shift to the seasonal system?
The merits of long-running anime are deep-rooted in several older series, which can be nostalgic and heartwarming as fans watch the story play out continuously, much like readers of their respective manga. The lack of long breaks allows for the emotional arcs of stories to be consistent, creating more depth and a special attachment to them. One Piece is an anime that has thrived in this format for decades and continues to do so today, rightfully earning its title as the King of Shonen. Still, maintaining that schedule is not easy to replicate.
In contrast to these merits, long-running anime run the risk of production problems. Some series struggle with creating a dependable level of quality due to having such a tight schedule. While a concluded manga series offers plenty of source material to work from, an ongoing manga incurs other risks. An anime could deviate from the manga, like Fullmetal Alchemist (2003), or include constant filler arcs -- which often have a bad reputation for lack of canonical stories, like Naruto: Shippuden.
With Fullmetal Alchemist: Brotherhood, the anime was redone entirely to remain faithful to its manga counterpart to the end. However, in the case of no authentic adaptation, fans can be left frustrated and disappointed.
These days, the seasonal format with anime like My Hero Academia, Demon Slayer and Attack on Titan is the more popular approach. This allows for a series to stick close to its source material with the extra time between seasons to polish up episodes and let the manga maintain distance. The breaks also prevent needing excessive fillers, but the hype per season can dwindle if fans need to wait too long.
However, these breaks can work in the anime's favor by keeping a strong quality of storytelling. For example, while the gap between Attack on Titan seasons can be frustrating, a long-running format would diminish the intricate pacing and storytelling set-up by the mangaka, Hajime Isayama. Thus, it thrives as a seasonal anime.
Hunter x Hunter (1999) is another example that adapted as much as possible through the Yorknew arc before running out of manga chapters. As a result, the remainder of the Yorknew arc and the Greed Island arc was released in three sets of OVA's, causing a fair amount of confusion among fans. The series would have been easier to follow if it was seasonal. However, Hunter x Hunter (2011) had an abundance of chapters to work with and remained consistent, adapting as much of the manga as they could at the time and becoming a highly notable long-running series in the process -- though that too ended prematurely.
While several long-running anime have become successful, this format is becoming less manageable among studios, hence increasing seasonal anime. The older format works well with an anime like One Piece, but it would weaken a series like Attack on Titan. Still, the tides certainly seem to be shifting towards all anime becoming seasonal, and there is no denying that most recent series have found merit in this approach.
Black Clover's decision to end could still turn out as a decision to shift to a season-by-season release schedule, maybe taking a Naruto: Shippuden approach of continuing under a different name or simply going on a brief hiatus. Its popularity and apparent goal of remaining faithful to its source material should be a point of optimism, and the choice could influence other anime to adopt the more flexible format.