There is (or at least was?) also an issue with front wheels with disc brakes pulling themselves out of the dropouts if the skewers weren't tightened sufficiently.

I guess the difference for me here is that 99+% of the riding I do is in good weather, and I haven't broken a spoke in years. So for me, disc brakes are an complex (relative to rim brakes) answer to a non-existent problem. I appreciate that it's a wholly different issue with tandems or anyone who rides in the rain or wet surfaces very much.