Aggrend posted about the dynamic layering system and how it interacts with the Ashenvale event as well as general info about it.
They tried disabling it for a bit but many complained about the world seeming “dead” so we are back to layers “collapsing” when certain thresholds are met.
I realize it doesn’t address the rares/taming concerns but I wonder if Blizzard would make it possible for an individual to in any way “override” the system that is programmed to rebalance folk. It’s sad to say but that could really be abused.
Best of luck to those on the hunt for that rare companion.