So, personally, the thing that makes me angry about Black Clover is not that it's a bad story, this is not.
If it was aFairy Tail stuff, fanservice and without too many pretensions or who knows what interesting ideas ok. But a bit like in old Naruto, there are interesting or engaging ideas, but they are not respected or at least they are always chosen easy solutions that end up detracting from everything.
Examples?
The death of Julius, in manga usually the death or sacrifice of mentors is essential because it serves to mature the characters, to make them grow ..... here? It didn't help at all, the only one to know is Yami who doesn't change at all, and Asta finds out only too late and therefore it doesn't impact on him as it should, to make us understand is as if Naruto had discovered the death of Jiraya only during the fight with Pain.
Why instead not let Asta and the others know about it before, with the revelation of William's betrayal attached? Could we possibly have seen cracks inside the knights, between those who were in favor of wanting to punish William and those who were not, would Yuno have been willing to save his captain knowing what he had done? How would he behave? It would also have been a good opportunity to deepen the figure of Yuno.
The slaughter of the elves? Another wasted opportunity, could be exploited to ensure that Asta and the others opened their eyes to the nature of Clover, they understood that it is not necessarily all black and white, it could be exploited to make Noelle grow even more, which possibly even with the help of the wisest royals would have made amends for the actions of his ancestors ... instead here is the demon, a character who as villain is a huge smart-ass solution.
Clearly having made the elves of the poor victims and given that the good worked for the royals it was necessary to fill that void with a narratively comfortable character, who in one way or another became a scapegoat for the problems of the protagonists. Seriously, looking at the manga it seems that the mangaka says: "See children? It's the fault of this bad guy if the royals acted like assholes, the elves died and the relationship between Licth and Lumiere was ruined". Which then is the same thing you risk with Megicula now.
The trial of Asta? Still, despite the ridiculous premise was an interesting turning point, this turning point could be used to create rifts between the Magic Knigth, between those who wanted to save Asta and those who didn't. Yuno could still be deepened, made to choose between his duty and his family. We could better understand the discourse of the royal families and really understand who controls who. You could use this to make Asta mature and really open your eyes, maybe for a while we would have seen a different Asta, more cynical and disillusioned.
Instead? Unlikely solution coming down from the sky (and also senseless since over ten chapters you don't understand which way they should change their mind about Asta), no consequences for the characters or for the story (Asta has remained the same and the matter does not seem to have touched it for nothing on the personal side, ditto for the other characters in the manga).
The Heart Kingdom part? Still, despite the not so exciting premises, the thing could be structured as an adventure to know the kingdom, its inhabitants, its magic system ... instead, as usual, everything was hurried, we saw very little of the kingdom and there is no time to become attached to the characters or their stories,
These chapters? Maybe in the head of the author Asta who makes the cool saving of the oppressed poor is nice, but personally I feel like asking "But how did this come about? What do I care about these guys? Who knows them?"
Ditto for the matter of the Spade war, it was introduced too fast, what do I care about these three guys?
Who can guarantee me that they won't be a flash in the style of the much praised Diamond generals?