Oh, it gets mentioned...along with pointing out the tendency for them to also squeal more upon application...but those voices usually get shouted down, typically with accusations of Luddite-ism. :-/

In the end, the tight pad to rotor clearances required on hydraulic discs are the result of using a relatively small braking surface at a relatively small diameter, and with materials that aren't super "grabby" (relatively speaking)...all of which means that the piston forces need to be quite high for a given braking torque. Since the travel is basically defined by the piston seal rolling (and is pretty much linear) this means (combined with the high force required) that the piston travel distance is quite small. It's a leverage thing...you can trade off travel for force, and vice versa. On many vehicles (such as cars, motorcycles, etc.) the pads actually rub almost all the time...but, those aren't powered by mere fractional hp "engines", so the additional drag isn't really noticed...it just is what it is.

Oh yeah...I've found that one of the nice things about using cable actuated discs is you can adjust the pad clearance up or down as necessary. Sure, that also means you need to periodically adjust them for wear as well, but that's a pretty minor annoyance. Folks tend to say that the cable-actuated models don't perform nearly as well as hydraulic, but that's really only true when comparing to ones that only move one pad and rely on disc flex to press against the other (such as Avid BB7s, etc.) Set up with solid, link-type cable housings, the power transfer on dual sided actuation models (e.g. TRP Spyres) really doesn't give up much, if anything, to hydraulic actuation IMHO.

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