The problem is the managing of the automation - the rearcrew called for the heading change, then the captain asked the co to select the heading so, by the time the heading actually changed it was far too late.
An instant hand-control input to change the heading could have avoided the rock or made the last minute 'f**k me' change of heading sufficient to avoid impact.
There has been much written and said about the 'children of the magenta' and the belief that more automation makes things safer - this accident happened to a perfectly serviceable aircraft with more bells and whistles designed to make the aircraft safer.
This is true, but the issue arose only after a major cockup had occurred. I suggest the primary target for any review should be why the cockup occurred, not why the sudden and unexpected need for an evasive change heading (or climb) was executed slower than it could have been.