[Suzerain of Sheol]

Well, that's the thing, they sent the 5 Istari across to help out in the war against Sauron, only... they nerfed them, to use a decidedly un-Tolkienian phrase. And to me, that's always struck me as a plot contrivance so that the story could be told. I can't see any logical reason why Gandalf and co. needed to be all subtle and indirect. That hardly seems the most efficient way of dealing with the problem.

And Saruman is a bit of a can of worms. The Book of Lost Tales goes into a bit, but basically, he was a bad apple from the beginning, too proud and arrogant to ever achieve the purpose he was sent for.