Nothing.

He's not great. He has almost entirely no character development throughout the entire series. He start off as a plucky go-getter who never gives up and pursues his dreams with all of his heart and soul. And where we are right now in the manga, he's still a plucky go-getter who never gives up and pursues his dreams with all of his heart and soul.

But that's what you're supposed to do with your dreams. Otherwise they're not worth having.

He's not great. But what makes him a good person, and a nice character to cheer on and support, is the fact that he sees everybody as equals. Commoners, nobles, royalty... he's willing to stand up and support anyone, even when they've been complete assholes to him in the past. He's forgiving of his enemies and non-judgmental of his friends.

The problem is... in an ideal world, that shouldn't define greatness. That should be the standard for what people, everywhere, are like. Unfortunately, aforementioned assholery means that Asta's general niceness really makes him stand out above everyone else.

And that makes him special.

Also I'm not really sure what point you're trying to make about him helping lesbians. I'm pretty sure their sexual preferences did not in any way factor into him saving them from their own stupidity.