Maybe I missed something.... Yes, he is playing a lot of notes, but if you're really listening, he plays the song from start to finish. He is not "running away" from the band, he is interacting with the band. I don't hear "immaturity", but a great deal of musical maturity.
He doesn't start "blazing" until the 3:54 mark, which is more than halfway thru the clip. Not only does he match the band dynamically, HE shapes in musical phrases. In watching the clip several times, I honestly don't see what makes him an "immature drummer." I am watching this clip LOOKING for things to call him out on... The only thing I can see is that he looks like Donkey Kong while he's playing. Thats all.
I just do not see it guys... Sorry.