HC, DB and SAS - all respected contributors here - have referred to the importance of training. I have NO IDEA whether quantity or quality of training contributed to this accident. However, if the industry is looking for areas in which to demonstrate it's commitment to improving safety, I'd suggest that increasing training beyond what is strictly mandated by CAA (which is mostly about checking) would be a good place to start.
I do understand that there are commercial implications to doing more training, but this "incident", surely, has shown that accidents, also, have commercial implications. The trouble is that, because the accidents prevented by training didn't happen, you can't demonstrate that training prevented them.
Recruiting sufficient pilots to allow a percentage of FOs to be allocated to post-graduate development training would cost a significant sum, I know, but so did the equipment. The two (pilot skills / equipment capability) should be in parallel.