There are still constraints, though. It has to retain the production bike's fundamental layout, certain key dimensions, features, and parts. The Panigale V4 uses a reverse-spinning irregular-firing-order V4, and that same description applies to their MotoGP bike. The Yamaha is irregular-firing but lacks the other features. The Kawasaki (and BMW and Honda) lack all of those. I also suspect that the Kawasaki's air ducts built into the fairing aren't as effective for downforce as everyone else's extravagant front wings.