> Would the CVR have helped in this specific situation?

In the next one, yes. Note the goal is not to do blaming and shaming, but to reduce anything similar happening, and to increase effectiveness of response. For example did multiple alarms go off, so it took longer for the crew to establish what the problem was? How quickly and effectively did the crew respond to the problem, and did the procedures they followed work effectively? How saturated were the crew with things to do? How well did training scenarios correspond to the actual event? How well did CRM work? [1]

As a result of looking at those, changes like the following could be made (and have been done as a result of previous investigations):

* Updating how alarms are prioritised and presented

* Updating flight management systems

* Updating the procedures to troubleshoot and respond to this kind of event

* Reducing workloads

* Updating training scenarios

* Using the incident as a good example of something being handled

[1] https://en.wikipedia.org/wiki/Crew_resource_management

Probably not, but with a 25 hour recording window one could make sure that the previous crews did not notice any irregularities (that they might not have reported) or anything else that might have lead up to this incident. That's pretty mind boggling that a modern age voice recorder doesn't even support storing the timespan of an intercontinental flight.

In this case the decompression blew away the reinforced cockpit door and the rushing air took away their checklist (and almost a headset) so they had to use the reference handbook (and/or do stuff from memory) so it would be interesting to hear how exactly it went. Also their communications were a bit confusing (no mayday?!) perhaps it was discussed in the cockpit.

No, but it would tell a lot about the response of the pilots, and whether they took any actions that might have endangered the plane more, even though the outcome was good.