I understand where your coming from but most people are just soo tired of Yuno get all of the spot lights about being great and all while Asta is pushed aside as if he's nothing so that's why most people want him to have a great backstory so much just to prove he is something just as great as Yuno. Or even better
I understand that, but still, that's even the whole point. Asta didn't need to came from royalty or something like that to be better than Yuno.
If he ends to be from any kind of royalty, then his all development would crash bc he will be what he wants to prove you don't need to be.
I would love more that Asta could came from a simple family who let him near the church due the attack in their town or that his mother were a meere poorly woman who loved Asta more than anything in her life so she leave him there before she dies so he could have any kind of life... don't know, but, don't make him royal, that's crap for someone so invested like him.
I said it before and I'm gonna say it again, Asta embodies the ideology that you don't have to came from the greatest house to do great things.
Stop asking for a great family past for Asta, that could make his whole development as trash. If they give a "greatest backstory" to him then it could mean that normal people can't do really anything good.
It's better for Asta to came from nothing, so he can proves to everyone that a simple orphan can become Wizard King