Good question and I get what you saying. For me putting down times towards the mid-top of an A-group is hard riding, keeping or gaining position requires smarter.
The continuing change in direction at the attached track beats me up no end. Sure I can ride quicker, easier than the average guy, but flat out I can't see how I can be more .. 'efficient'. I try be as smooth as possible as I have no electronic nannies. On similar machinery, I feel weight definitely plays a part in brake distances, brake forces and asks more of the tyres. Rider fatigue with continuous direction changes, moving myself off one side, over and onto the other, I don't see how it would be the same effort for a smaller lighter guy.
Insight and advice accepted