What you, unless I'm mistaken, describe is the battle regimen system, someone would:
Open/Start a regimen
Add a skill/spell
then others, who wanted to, would add their skills/spells
Person who initiated would then execute

Order mattered for the sake of achieving different effects, and different skills/spells in different orders achieved different effects. There was a time limit imposed on adding commands to the regimen queue so you couldn't just leave it open from the start of a fight and use it when ever. It had the potential to be a great system. Sadly the execution of regimens didn't work right, there was no AA, and once you started/added to the regimen you were unable to act until it was executed. It failed ...

In the longer fights where damage mounts mages couldn't add spells because it stopped them from healing, it slowed DPS with melee just standing still, tanks couldn't get involved because they needed to spam skills to hold hate.

Assuming they "fix" those things and return it in 2.0, which has been mentioned in a few places, by the dev notes. It still has the potential, as long as it doesn't lock us out of being able to act in other ways, and now with AA it wouldn't completely ruin DPS anymore.