catzeye
Writer's Block
It's certainly possible Leon isn't the villain, it's just that whenever a synopsis or character description says, "This new character is super strong and beloved by everyone." It usually turns out they're either a fraud, not a good person, or both.
While I'll agree with you there, I do think this time Leon might actually be legit. I actually did a bit of research on his namesake (Leon is named after the dandelion). The symbolism of a dandelion has overwhelmingly positive connotations. Now that doesn't mean GameFreak can't make him a fraud or evil, but I think it's unlikely. Now his brother Hop has a namesake that has some darker connotations.
I think the reason we're seeing him so early is that we're going to get a chance to really see a champion as a human being, and not just an enigmatic and powerful figure. Since GameFreak likes using family's in plots (like in Sun and Moon) I'm have a theory that we'll be seeing a strained relationship between Leon and Hop that sours once Hop begins his journey. I also think we'll see Leon maybe not all that happy in the role. Maybe he really is that good and is tired of not having a real challenge. Or he is tired of not having much of a private life. I do think he lost to Sonia once in an unofficial battle though.