avanti - I would maybe rephrase 'struggling to cope' as the ATC probs don't really affect actual flying a/c. I would say that rarely a sector can get too busy for very short periods of time, but we have measures to cope with 'overload' by splitting sectors into smaller areas, or having a second controller listening in and monitoring everything. I think 'struggling to cope' is to do with the amounts of a/c wishing to fly during peak times, hence the reason why getting airbourne from LHR and LGW without a slot time these days is such a rare thing. Hopefully the new centre together with the pending airspace changes (in 8 days) and RVSM will permit more a/c to fly through a sector in an hour than at present, therefore reducing delays, so we are coping better.
On the general point of the thred by SB, with all the technical and electrical advances both ATC and a/c have, it is getting much harder to get a 'mid-air' or terrain hit. However - more equipment, more to go wrong! A/c with good servicing shouldn't crash, unless the jockey up front 'makes a boob', or likewise ATC pass dud info.