I dunno, I'm starting to see a lot of sports bikes out there.
Less of a hitbox, more speed, and tighter drifting apparently.
I think it's pretty balanced. Some of the karts have higher speed. Also the drifting advantage is more arguable this time.
With karts you have to plan your entry a little more carefully in certain situations, but in the middle and exit of turns you can actually get a tighter drift than the inside drift bikes. Whereas with the bikes, you can make a later sharper entry if you so desire, but in the middle of the turns and on exit, it can push up towards the outside if you aren't careful.
And no wheelies.
I think I see the Formula One cars alone almost as often as all four inside drift bikes combined online. imo there's an actual choice this time around instead of "use the sport bikes or you can't compete".