Honestly I don't know how much that is worth really. Playing private for-fun matches with a few players (regardless of how good they are) is not comparable to having thousands (or tens of thousands or whatever) of people that are trying to win as easily as possible. This phenomenon is pretty evident if you look at any PVP game that gets launched with something OP/broken that somehow missed the playtesting.
We've discussed UD 3 a few time so I'd like to avoid repeating same points but generally speaking I agree that Undisputed is considerably snappier which makes the gameplay feel smooth especially when transitioning from striking to grappling. However, I find footwork and sways really janky in Undisputed. Also, while Undisputed is flashy I think the actual mechanics are quite hollow. For example, I would attribute Hendo's dangerousness in UD 3 to the game's punishing damage system that feels good despite the limited striking mechanics.