Who said anything about using Muse Tariqah in an idling build? Terra's Staff is for idling in, or Genbu's Shield if you really insist on keeping Templar Mace equipped.
It didn't really need to be said... as it turns out, the only situation where Muse Tariqah is even worth equipping at all is Cure V. So unless the debate is about Cure V, Muse Tariqah pretty much loses by default. That being said, is it even worth the inventory space to add MND+4 to your Cure V? Unless you're actually pulling hate enough that spell interruption would help? (In which case, I'd still say Legion Scutum would be better to reduce your enmity.)
At best it might be ok if you're fighting something that you know you'll take AoE magical damage from and against which you have an appropriate Barspell cast
You say it like this is an uncommon scenario. The WHM should generally be able to avoid most AOEs but mistakes happen. People draw hate into the mages, or the monster gets uppity and you gotta move around a bit to cast on folks, etc. Elemental AOE probably accounts for 90% or more of the damage I take on WHM.
I would be wearing Seveneyes and Nms. Shield +1, which is what I assume he idles in.
Yes that is correct, I idle in Seven & Num+1. This is also my second choice, my first would be to idle in dmg- gear. However, I don't use Spellcast or Windower macros, and 6-line macros can be rather limiting. Thus my standing gear incorporates quite often my most commonly-used spellcasting equipment in each slot so as to reduce swapping in each individual macro to a minimum. It's kind of a compromise, I know, but I refuse to go to a multi-macro system where in order to cure someone I first hit a macro to swap into Cure gear then hit my Cure macro...