Yep, the fork crown can be more compact allowing a lower drag arrangement in that area.
RowToTri wrote:
.....but perhaps even more importantly, this could allow for a lower stack geometry, right? A lot of triathletes complain of trouble getting low enough on the current crop of superbikes. If a disc brake allows for a bike that can get you into a better position, that's going to be a bigger deal than the drag of the brake itself.....
....What do you guys think?
I think the geometries available are a function of demand, and as Dan would say "orthodoxy", rather than any limitation placed on the stack by the requirement to facilitate a rim brake. In the smallest sizes, the head tube may get short enough to slightly compromise stiffness when combined with a 700c wheel and a rim brake. But 650c wheels are there as are other options to drop the bars. Besides, most complaints about bike stack come from those of more average proportions and it's simply that they want something more aggressive than the bulk of the market. I don't believe there's a technical limitation imposed by rim brakes.
Having said that, I'll happily buy disc brakes in future.