Inquisitors are the pinnacle of the cleric class in my humble oppinion.. the debuffs we use are absolutely devastating for mobs
I tend to do things in the following order when a tank pulls:
Forced Submission
Mark of Pawns
Bestowal of Vitae
Reproach
Inquriti (or whatever that one is called)
Weakness
then i follow up with BoV after that
I only do this on really tough mobs like Yellow ^ ^ and up... I only use Forced Submission when a group of regular mobs are pulled.
I hardly ever have problems keeping tanks alive if they aren't total wimps and usually end up with 70% power after a yellow ^^