Sky9 : Remember difference between TA and RA is max 13 seconds ( above FL200 with SL7, 48 sec versus 35 ) or a litle more than one radar return.
On the turning issue :
Turning both aircraft a min of 30 degr to avoid collision is still very effective , even at short range.
In the ZRH collision this would have worked , even 30 sec before , both a/c would have been cleared by more than 1NM . If the turns would have been combined with the descent clearance as the one issued, they would have had 700 ft vertical as well.
But of course afterwards everyone is wiser...