AIPA did issue such a directive many years ago, but that was a response to political noise sharing (exactly as Keg said). It never had any influence on SYD airport modes to my knowledge
Yes it did influence the mode operated as the requirement to land 16R often led to a change back to parallels ops.
The XW criteria was 25 knots, its now 20 knots. As I said it could be 15 knots or could be 30 knots. Its up to CASA and I guess the airlines. Increasing the XW criteria "too high" could lead to more off-mode requirements which have safety and efficiency considerations. Examples - landing aircraft requires RWY 25 when operating 34 parallels.