Well, the Theoden bit was just Tolkien's reworking of the Grail King/Parsifal story... the healing of the wounded king and all is right again with the people and land. Knew his mythology and legend, did J.R.R.

Always go with the archetypes. They hit home readily with the audience.

Saruman was another one; in his case, his downfall was caused by his studying too much and relying too much on what was technology in Middle-earth (plus a bit of good old-fashioned jealousy of Gandalf for the respect he engendered). Tolkien was quite a Luddite, by all accounts--he hated the "dark satanic mills" that were taking over his rural "green and pleasant land.