Horizon's Knight

thank you for your faith in me.

People are just bandwagonning on him. I voted for someone else XD

Nope.
I can see it a lot more than I can see SoKai, as they at least bothered showing me Xion sees Roxas truly as a friend as opposed to Sora that sees Kairi as another friend, but Roxas shares Kairi's obsession.

Let's conclude it with him being a game mechanic element XD

It was. Playing on Standard now. xD;
What brought this up though?

Ah, I see. You read the impressions XD;;;

KH3's going to be the final game in the series, or a major point towards it. I should hope they'd deal with Sora's Darkness, especially since Nomura seemed aware of it, and 90% of the series' plot atm is the mess that is Sora's being.

I think you're overthinking this. And that's coming from me.
Sora has Darkness. I personally believe that Anti Form was the whole reason why he was given the Drive Forms - to ventilate it on occasion to keep him from becoming a Heartless. The kid's been through enough on his own without needing Namine, Roxas or Xion affecting him into it.

The fact it had Darkness and it was once a Heartless. Anti form was never properly explained after all.
And despite Sora not being a Heartless, arguably, the fusion between him and Roxas isn't complete due to how it was carried about.

Nomura confirmed Anti form relates to his time as a Heartless. And purifying means she pushed the Darkness away enough for him to regain his sense of self. It doesn't mean the Darkness went away, least of all all of it.

It was purified from Riku's Body, to be precise. It wasn't quite a Heartless from the get go if you ask me.

Well, Sora's Heart was also purified by You-Know-Who's pure Heart. Yet, that didn't stop Sora from becoming that-thing. Also, knowing Xehanort, I doubt his Heart will stay normal for very long (considering Xehanort Heart was even normal to begin with).