Sora isn't even made by Disney to have "Disney boy" as some sort of nickname. Ignorance there made me laugh a bit.
I honestly have to say that Sephiroth wins, for having more impressive abilities and feats, and more power (actually, all the power is in the Keyblade which Sora uses pretty much) and I'm just talking about AC and CC showings. If Sephiroth is the one-winged-angel supernova creating being in the last battle of FF7...then wtf can Sora do about that. Time stop may help, but given that there are magic-based invulnerablities, who knows what that may do.
As a side fact, Sora and all of Kingdom Hearts is underrated. All the talk of "all the FF characters are nerfed" is a generalization and a lie. If the person means the FF incarnations simply had more screen time and showings, then yes, as per KMC they are stronger, but the claim they are nerfed is not SE-supported, not in the least. With Sephiroth, I think it's a different story.
Also, Tidus, Wakka and Selphie are exceptions, as well as X-2's YRP. In other words, when it comes to Cloud, Yuffie, Squall, Tifa and Auron...just what about them makes them seem weaker? We've fought alongside all of these people. In fact, I've seen Cloud and Auron move faster in KH. Damage points, I'll laugh if someone brings that up this time around.