Poo and Cat seem to have belt drive figured out. And Doo's chain case setup has not been without problems the past few years.
Belt drive is less overall weight and importantly, less rotating mass. That is something that would improve Doo's handling since it's motor and clutch setup put the rotating mass up much higher than Poo and Cat.
Mass centralization is great, except if that mass is up too high. That's where Cat and Poo have the advantage on Doo. Try riding them back to back and you can feel the difference.
Hopefully, Doo is working on that fix and the steep attack angle on the Doo skid for the G6. There is so much great stuff in the G5, but it can be improved.