CX's mistake is offering anything by way of a customer service gesture as it only whets peoples' appetite for more.

Fuel diversions are a fact of life on a planet where weather conditions are variable. Crew changes are part of that as there are safety rules which set the maximum number of hours they may work.

The alternativ here is an aircraft going into the ocean for lack of fuel or a tired crew member making a fatal error.

Better to send a note to CX thanking it for putting your safety ahead of its profits (as it is close to a certainty that a fuel diversion and a five hour delay turned this flight into a loss-making enterprise).