Fast is fast and class is class, whatever the discipline. The thing being that a class rider (GDS) would be beating others on any course, not just one of the "fast" courses, which makes the whole question of absolute times a bit odd. More to the point is that certain riders are sticking considerable time into other class riders, and for me the differentials are the important figures. Placings and differentials should determine who gets to ride in an oversubscrbed event like a national, not absolute time, which are a result of a combination of factors most of which (weather, traffic(!!), for example) are beyond a rider's control.
The bottom line is that if the championship was held on a "sporting" course with hills and corners, the same group of riders would tend to come out on top, possibly in a different order, but they would all be in the mix somewhere. Anyway it's hard to see past an on-form Alex Dowsett if he takes the start. The man has simply massive power outputs and can sustain it for quite long enough to do the job.