If there must be a breakdown, I’d rather see it done along the same lines as organized events. Age groups, or racing categories.
There aren’t any races run like amateur wrestling! (Weight class).
That said, Zwift’s target market will include more than just bike racers. Strava has weight-based groupings.
Here’s something Zwift CAN do, that Strava can’t… Classification based on w/kg. zwift could track w/kg for the hill and sprints. Keep track of everyone’s max.
Then, group rankings based on those numbers. While Zwift uses the honor system for your weight, your max watts are recorded in the system.
There would be no “cheating the system”, because any new max scores would be used to classify you.