In the interests of full coverage, we'll mention this one, but don't keep your hopes up: the latest build on the PTR has reverted the Nature's Swiftness and Elemental Mastery sharing a cooldown change, so Elemental Shamans will once again be able to crank out an instant Chain Lightning or Lightning Bolt crit. Unfortunately, they shouldn't count on it, as lots of changes have gone back and forth on the PTR. It could be that the next time the PTR comes up with a new patch, this change will be right back in.
But it does serve as a reminder that no matter how bad some PTR nerfs may seem, nothing is finalized until it hits the live realms. The Test Realm is for testing, so we shouldn't be surprised when Blizzard does exactly that with it.