Kingdom Hearts doesn't deserve to be anything above Tier 6. All of the current ratings on the profiles are wanked and don't work realistically.
Tier 3 Scaling Flaws
Tier 3 is wrong for many reasons. The game, Melody of Memory, basically unconfirmed any sort of scaling to True Kingdom Hearts. Xehanort didn't get to use its full power before Sora pulled a victory over him.
The X-Blade doesn't scale to True Kingdom Hearts either. The entire reason for it was for a statement calling it the counterpart of True Kingdom Hearts. However, the counterpart doesn't prove it scales in this case.
coun·ter·part
/ˈkoun(t)ərˌpärt/
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noun
1.
a person or thing holding a position or performing a function that corresponds to that of another person or thing in another place.
Counterpart clearly just means that it's necessary to access and help command True Kingdom Hearts like what Xehanort did here. It doesn't scale to the full power of it physically. Melody of Memory dialogue from Kairi would suggest completely otherwise. Not only that, the fact that Aqua could even comparable to it at all is a massive anti-feat. The X-Blade would be scaled to wherever we're downgrading Sora and co.
We've already discussed why the Re:Coded stuff doesn't work before outside of this thread and on many other threads. There's no reason why that has changed now. It would be an outlier regardless.
Tier 4 Scaling Flaws
This is also flawed. First of all, why did
anybody think it was a good idea to scale Twilight Xemnas off the door to Kingdom Hearts' feat? Like literally,
Ansem got his ass one-shotted by it and that's a dude who could contend with Sora pretty evenly. That already casts pretty heavy doubt on the situation, but the Kingdom Hearts that Xemnas fused with
was ruined, going by his own word when Ansem the Wise's machine was shot at it. We cannot scale Xemnas to something like that when he fused with an incomplete version of it. It'd be an unquantifiable boost that might give him an "At least" rating but that's it.
Ansem was never amplified by all of the worlds or anything like that. It's headcanon at best and not supported by any kind of dialogue. The current reasoning on his profile is completely wrong. In addition, destroying Radiant Garden is a feat similar to what the Heartless do to other worlds, which was already rejected when attempts at getting Tier 5 - 4 were requested through it.
Spellican's feat is outlierish and not something Sora even scales to at all. It should be disregarded.
Xehanort wrecking the Land of Departure isn't a Tier 5 or 4 feat either. He didn't do it on a significant enough scale for this to truly be the case, especially with how it still appears from when it gets transformed into Castle Oblivion.
Zeus' feat is done by Telekinesis, which makes it incredibly doubtful if that should even scale to Sora at all. Considering being a
higher tier off of TK is nothing new, I believe it's consistent with the rest of the series that Sora doesn't scale to this either. That seems correct regardless seeing as how Sora outright stated his lightning spells were nothing compared to Zeus.
Suggested Revisions?
Kingdom Hearts should be fine to stay at 3-A. Actually, I think it might be the only thing in the verse deserving of an upgrade to Low 2-C - 2-C, but they should not scale to it.
Xehanort and Vanitas can get a note that they'd be 3-A overtime or only with Kingdom Hearts, not physically as they would downscale to the rest of the cast physically. At most, they could get an "At least" in these keys. The same applies to the X-Blade.
All of them should probably be somewhere in Tier 8 or 7, but they might be Tier 6 based on the Heartless Hans feat. That would need to be accepted though. Speed is also something that's going to be needed to be downgraded to like Massively Hypersonic, maybe FTL at the most.