In a priority system, you use the 1st ability whenever the qualifications dictate. In this case, that would be to use heavy thrust whenever the buff is down.
A exception most likely being made for when you’re in the middle of a combo, but that’d require some more advanced math.
The lack of proc based skills in this game means every class has a rotation. It’s just these rotations are the result of skill priorities, either due to keeping buffs up for simply using a higher damaging skill, so that it’s easier to present it with a priority list.
I’m pretty sure if you were to have different people look at this list and tell them to come up with the ideal rotation for a tank and spank, they would come up with the same exact rotation.
But after saying all that I do agree with you, what OP posted is definitely a priority list and not a rotation.
attacks off the GCD don’t break combos. So if Mercy Stroke and Leg Sweep are off cooldown, you can throw them in. Speaking of which, if mechanics, or the raid, doesn’t need you to use a stun, Leg Sweep is a free 130 potency attack every 30 seconds.