1) Tell me, what more goes wrong with the caliper? I've never had caliper issues.
2) How do you quantify snappiness? Does it come from a stiffer frame or a flexier frame?
3) You know what detracts from my ride quality? Repeated braking from 45-50mph to 20mph on steep descents with hairpins and carbon braketracks having poor thermal conductivity. The lack of initial bite on even the best textured carbon rim braketracks from ENVE, Mavic, Zipp, Campagnolo. The braketrack wear after 3-4 years and a couple million feet climbed/descended. My brands new Campy H11 rotors have brown discoloration on the tynes from heat. You're putting the same energy into a rim brake system, and if your using CFRP rims, you're relying on that heat not melting/delaminating the composite.
1) Thats exactly my point. Air bubbles in brake lines, bleeding, readjusting lever throw, bent rotors, pad contamination - Discs are a pain!
2) Not sure how to respond to this one - the only data I have is subjective feedback from a number of people; I'm certainly not the first person to suggest that discs interfere with ride quality. As for flex/stiffness, its definitely stiffness - the forks and dropouts are reinforced to withstand the higher forces applied to the frame whilst braking. Snappiness/responsiveness is not a property the directly co-varies with stiffness.
3) You're using the phrase 'ride quality' in a completely different sense than the way I've used it so the criticism doesnt apply. But yes, braking is worse for calipers and as you suggest, does have the downside in that it eats up your rims. But with the mini-mountains in Australia, I've had no issues with carbon brake-tracks.