250 Euros for each passenger delayed by a cancelled flight even if it's down to an engine fault or perhaps a cracked windshield? Both of which happen from time to time and are "inherent in the normal exercise of the activity of the air carrier" Both can take time to diagnose/repair/replace.
Short of having a second fleet of spare aircraft, there are always going to be issues arising from airline operations. Unlike a rail operator who can run services with faulty rolling stock (eg flat wheels, broken A/C, broken PA) an airline operator is both morally and legally obliged to provide an aircraft which is servicable to a far higher level eg faulty PA can be a no-go item and may not show itself until 5 minutes before boarding.
Fair enough companies who regularly take the piss deserve it, but those who try and provide a good service are going to get stung by this. Say good bye to the 50 Euro ticket