Personally I abhor trying to fob off the passengers with excuse number xx from the big airline book of excuses and I feel that paying passengers have a right to know the real reason behind delays.
On a fair few occasions I have gone up to the gate desk and made announcements there. I feel that if the information is given early enough that there will be significant delays then any passengers who may not wish to then travel can make that decision informed and early and it gives us the chance to offload baggage if required. In my experience businessmen, a solid backbone of my company's revenue payers, want info early as they might miss their planned meetings thus making the trip pointless. I have been onboard other carriers as a passenger when we were herded onto the aircraft on schedule, doors closed and locked, off pier and remote holding before we were told there would be a three hour slot delay! I would like to avoid that scenario whenever possible.
Communication is indeed the key, the problem exists within this scenario is 'did the crew feel that their explanations would be adequately received, and thus the situation, when on board, calmed?'. I would probably guess not.
Enjoy