I seem to recall reading an interview with a previous winner and he mentioned the rules state you have to play/compose to different genres as part of your time. No particular genres, but it ends up dissecting the solo into chunks that a lot of the contestants find difficult to seamlessly weave together. Most use a drum pad to work it out, although I believe you can also use backing tracks, but maybe not.
It really isn't just a drum solo competition anymore. They are judged for showmanship, too (stick tricks and all), and other parameters.
I do not believe everybody is meant to do the Akira Jimbo-thing. If they just let these kids play for 5:00 and do their own thing and let it sink or swim on that foundation it would be far more natural.
It seems so odd. I never saw Billy, or Lenny, or Weckl or Vinnie or so many of the other greats do any stick tricks. Now it's considered mandatory for the drum-off.
It's the same thing as the WFD gig. Speed has become mandatory for people to be impressed with a solo. I still like Toad 45 years later. Even the solo from Ron Bushy, In-a-gadda-da-vida. That solo was mandatory for gym bands back in the day. Nothing fast, but musical, they were.