Considering Sora only makes LS stop fighting him, and has to struggle hard to do it, while LS can basically one shot him, that doesn't exactly make it look like Sora is far superior to him.
Gameplay and story segregation. Sure an unskilled player can lose to Terra's LS, but it doesn't change the fact that Sora canonically beats him. --- Oooh, MM, he be tryin' you, dawg. He be tryin' you. Best mind you biiiiiiiz-ness. ~KMA *triple z snap* ~AluminumTicket
Another pure story example that Sora and Riku have far and surpassed TAV.
I mean put this in perspective right now Sora and Riku are more or less equal. Terra is at his strongest at the end of BBS and in order to beat Old master Xehanort he had to unleash his darkness and was still breathing hard at the end. Riku went up against a Young Master Xehanort and kicked his ass without breaking a sweat, if we're to believe that the time rewind happens and Riku failed to beat the clock the first time around then that means Riku built Young Master Xehanort's ass multiple times and STILL was going strong.
Beyond that both direct super upgraded Terra and direct super upgraded Ventus have been defeated by Sora and Riku respectively.
If we go into a gameplay perspective (which there is very little story and gameplay segregation baring certain mechanics like game overs) Sora and Riku are not only capable of doing everything TAV can do, they can do everything TAV can do but better. Beyond that Sora and Riku are beyond powerful when it comes to their pure physical abilities. The only way for TAV to even remotely keep up is using keyblade transformations, but Sora and Riku don't need transformations to do amazing physical feats.
If Sora and Riku see a large steep mountain they don't need to have a vehicle to fly up it, they can jump up it with ease. --- I've got a quote that embodies you perfectly, but it's seventy-three posts long, has a few massive flowcharts, and lots of Xion-KMA to Me
I kind of figured out that Sora and Riku must be significantly stronger based on heartless. The only Heartless you fight in Birth by Sleep are Shadows, Neoshadows and Darkballs and they are ridiculously strong.
There is also the factor that these are within the realm of darkness but Mickey showed he could take out Realm Darksides with ease and he can't be that much stronger then Sora and Riku.