Basic rules of thumb...

*Anything* that can be accomplished through the WoW scripting/macro system is fine per the TOS. If Blizzard doesn't like it then they will simply change the UI to no longer allow it or change how it works (Decursive for example)
1 action per client per key press is also fine per the ToS. No matter if it's done through software or hardware solutions.

Any sort of unattended game play, or multiple actions per single key press, or delays or things like that is not allowed.