[Child of the 7th Age]

Interesting topic Sardy! And good points Raynor. But regarding Aiwendil, I would argue that he did retain mastery of shapes and hues, even as an istari.

Quote Mithadan:
But again, what of Radagast? Could he change form? He was a master of "shapes and hues".

Quote UT:
Originally Posted by The Istari
For with the consent of Eru they sent members of their own high order, but clad in bodies of as of Men, real and not feigned, but subject to the fears and pains and weariness of earth, able to hunger and thirst and be slain; though because of their noble spirits they did not die, and aged only by the cares and labours of many long years.

QuoteRaynor:
I don't think he constitutes an exception in that regard; if anything, he is lesser than Saruman and Gandalf. I believe his mastery involved what he could do to his environment/others, not unto himself; after all, Saruman has his voice while Gandalf wields the flame of Anor.

It seems to me that the answer to this particular question depends on how you view "Man" in the context of Middle-earth. Surely Beorn was a man, and yet he was also a skin-changer, able to take on the form of a great bear. If Beorn the true Man was able to shift shapes, then why couldn't a Maia in the form of an istar also possess this ability?

Yes, I know we can rationalize Beorn's abilities and make him a beserker in a bear skin rather than a true bear, but I do not think this is what Tolkien intended. Certain characters in his Legendarium still have one foot in faerie.

The critical point here is the way we interpret the race of men. Perhaps the "Man" of Middle-earth could exhibit somewhat different characteristics than those we now regard as typical for modern man. Not only do we have the example of a shape-shifting man in The Hobbit but just look at how long the men of Numenor lived. Their lifespan far exceeded that of any "normal" human.

It is very true that the istari had to take on human form, which meant they were subject to hunger, weariness, and even death. But at the same time I don't think we can automatically assume that our own ideas about what a man is and isn't were exactly those that Tolkien held.

Note also the wording of this text in UT that pertains to the istari :

now their emissaries were forbidden to reveal themselves in forms of majesty, or to seek to rule the lives of Elves and Men by an open display of power.

The italics are mind. Why would Tolkien have included a word like "forbidden" unless he thought that the wizards were more than mere broken down old men. Surely this implies they did have some remaining ability to take on more majestic forms and to wield great power over others? I have always thought that the restrictions placed on the wizards were not always physical in nature. While their human bodies had limits, the greater limit was surely the oath of obedience that was placed on their heads by Manwe, his instructions that they teach and show and win trust rather than overpowering the inhabitants of Arda.

When Gandalf died and was remade, how much of this was a physical remaking and how much was simply taking off the restrictions that had bound him up till that point? There may have been a little of both involved, but wasn't the removal of the restrictions really the most important of the two?