Radagast in The Hobbit Film (SPOILERS)

[Legolas]

I was disappointed in Radagast's portrayal as a whole. McCoy was a potentially worthy choice, and the more serious parts of the role were done well. I'm also okay with him being a little silly or spaced out.

Unfortunately, the extent of his stuttering and hyperactivity overshadowed that - especially with how heavy they are when he first appears. That first impression will stick with those just being introduced to him, and I think that's a pity.

He could've been a bit more absent minded than the condescending Saruman or the warm, personable Gandalf, but a bumbling clown smeared with bird droppings was not at all what I had in mind.

Originally Posted by Gothbogg the Ripper

I am glad they showed Radagast as the cowardly simpleton he was.
His apathy during the War of the Ring has always been absolutely indefensible to me so it was nice to see both Gandalf talking down to him like a child and Saruman ranting about the guy and his poor personal hygiene.

One of Tolkien's most intriguing characters and perhaps one I hate the most. A villain is expected to do evil things, a hero is expected to act with virtue, but someone so completely indifferent is just infuriating to me.
It suggests cowardice, something untrustworthy and rotten.

I don't think any of it is his fault, though. Radagast was miscast. I don't mean in the movie, but for his Istar role in the actual war as an emissary to Middle-earth. That Saruman had disdain for Radagast does not surprise me in the least as Saruman often comes across as dismissive. When someone is in the least bit a hindrance or threat to him or his rank, he gets cranky.

At the council when the Istari were chosen, there were initially just three planned, and only two volunteered: Saruman and Alatar. Olorin was summoned by Manwe as third, Alatar brought Pallando as a friend, and importantly, "[Saruman] took [Radagast] because Yavanna begged him." Aiwendil [Radagast] was not banging down the door to go himself.

His 'boss' roped him into it, and after we see how it plays out, it seems entirely probable that it actually went as intended. As the council had originally "resolved to send out three emissaries," Yavanna could have seen no harm in including a fourth of her own, set out to look for creatures that the other three would not have the time or purpose.

There is no hint of an explanation of why Yavanna's evident desire that the Istari should include in their number one with a particular love of the things of her making could only be achieved by imposing Radagast's company on Saruman; while the suggestion in the essay on the Istari that in becoming enamoured of the wild creatures of Middle-earth Radagast neglected the purpose for which he was sent if perhaps not perfectly in accord with the idea of his being specially chosen by Yavanna. (Unfinished Tales)