Until you have enough defense to be crit immune, that is a threat.
In Wrath, a mob has to exceed your level by 4 or more to land a crushing blow.
The highest mobs in the game are bosses which are considered 83rd - at 80th you'll never receive a Crushing Blow.

So far I have only one mixed group.
I've broken my dps down to Opening Moves and Spamming Moves.
My opening moves is a cast sequence, where the paladin does the first three moves (Seal, Avenger's Strike, Judge Wisdom).
Every other character passes on the first two keypresses and does a Dot type effect on the third.
If its a tougher opponent, this key is two more dot/debuff type effects for other toons but nothing for the pally.

My other dps key, is the spammable dps mash for other toons, and a basic cast random for the paladin.
My druid, who heals for this team will Faerie Fire on the initial debuff/dot button (and moonfire/insect swarm if I press it two more times).
The druid has a castsequence reset=combat !Wrath in the dps button, so she helps to kill trash but has no GCD's in the way of her heals.

Everyone has a set up that works for them, it just takes a while to learn it.
You'll learn yours.
Plus, you can borrow from what works for others, to tweak and improve your set up over time.