I think a better technique would be connecting all EGCs together every chance you get. That reduces impedance during a fault causing the breaker to trip quicker. It is also my belief that 250.148 requires you too.
Yes, in multi-gang boxes the number of EGCs can be a headache to join but it's not impossible.
Make the groups you mentioned, or get connectors that are listed for more conductors, try leaving one long bare EGC to 'loop' through all the device ground terminals etc.
Im glad you mentioned leaving a long EGC and looping through all devices because that's what I do and so I'm glad someone like yourself considers it an acceptable practice.
So to sum it up, the way I have been making up my switches boxes thus far, keeping EGCs of each circuit separate, poses no hazard as far as switch yokes having different potentials, but by splicing EGCs of multiple circuits together whenever possible (junction boxes, switch boxes, etc) you create multiple paths back to the panel thus lowering resistance, tripping breaker faster, and if one circuit lost its EGC between the panel and the splice, there would still be a path for the fault current and trip the breaker.
Also most folks believe 250.148 requires all EGCs to be spliced together I have seen.
All around it's just a good practice to splice them all correct?
Thanks for the time on something so basic :thumbsup: