This could explain the problem Rattie and me had yesterday with just loosing a Kill Command GCD.

TipATTN: Custom Lag Tolerance was automatically set to 400 for a lot of people. If your spells feel off, this is why. Here's how to fix it: (self.wow)

/dump GetCVar("SpellQueueWindow")
To see what it's currently set at. You want it to be at your normal latency. So, if you normally get 60 ping, you then want to type
/console SpellQueueWindow 60
This fixed a lot of issues myself and friends were having with game abilities feeling off.
Edit: check out /u/freddy090909 and his post below. While this fixed all my problems for me with not being able to queue up spells, there may be some side effects.
Double edit: if your ping feels off, apparently the old "default setting" was 250. Try 250 and see if it feels like pre-7.2 casting.

Here is a link with full info:
https://www.reddit.com/r/wow/comments/6 ... cally_set/

Ohh cheers Begemmot