Radagast the Brown??

[Aiwendil]

Regarding the issue of Radagast's and Saruman's respective "failures", I think something I posted in one of the chapter by chapter discussions is relevant:

. . . it seems that often when we are presented with a natural extreme and an artificial extreme we are also given a sort of happy medium. For example, Saruman is artificial, Radagast is natural, and Gandalf is the ideal balance. Others that occur to me:

Aule (artifice), Ulmo (nature), Manwe (balance)

Feanor (artifice), Finarfin (nature), Fingolfin (balance) (in this case we also have Fingon and Finrod, just a shade to the artificial and natural sides, respectively)

Noldor (artifice), Teleri (nature), Vanyar (balance)

No time to elaborate, alas - but I would say that Saruman and Radagast each failed (though in very different ways and to very different degrees) by erring on one or the other side of the balance between Art and Nature.