As a Rogue, you could
/cast Cold Blood
Those are actions that aren't governed by the global cooldown. Secondly, those actions are supported in WoW's interface.
Warcraft 3 had cheat codes. This does not mean that any and all subsequent games have them nor should have them.
As long as we are not using 1 button to use 3 attacks that could not normally be used together as they all require an attack turn.
As long as there is not a programmed timedelay.
For example, using a macro to swap your gear is generating up to 13 clicks with one action. Thus, it violates the one click per action rule.
However, creating a "macro" on your mouse that say does SHIFT+1 does NOT violate this rule as you can normally use a shift modifier anyway.
However, if I was to program it to instead to SHIFT+1 > SHIFT+2 this would clearly violate the rules as I am performing 2 actions with one keypress.
The difference between using the WoW interface for macros and using a 3rd party for macros is that Blizzard controls what actions can be performed when pressing the button. Casting more than one action that requires a global cooldown is possible, but you MUST press the button twice.
/castsequence Wrath, Starfire
This is multiple actions performed across multiple keypresses. Thus it is a legitimate way to use WoW's Macro Interface.
Diablo 3 offers no such functionality. Therefore, any modifications outside of the game to change the way the game operates is against the rules.
MVP's are not employees of Blizzard Entertainment. We are players just like you.
Nothing I say is Official word from Blizzard, everything is of my own conjecture.