It's already a nightmare driving on Motorway compared to 10 years ago, no one follow any rules anymore and motorway police don't give a damn about anything except speeding. Imagine you going at 120 and suddenly a bike doing 70/80 just suddenly change lane and end up right in front of you, imagine a bike cut in front of you and then apply brakes and slow down. Imagine yourself stuck behind few bikes all trying to overtake each other at 60/70/80 KM/H.
I think the 500cc rule is good.
I would like them to put a ban on rickshaws on certain roads in the cities too. They travel at 30/40/50KM/H and often block the whole 3 lane road while overtaking each other slowing down the flow of the traffic.