Psychological depth in Tolkien's characters

[Eurytus]

I, myself, think that the story about Gimli and Legolas has its own charm. They are two completely different people, but yet, they are on the same quest together; to destroy the ring, and protect Frodo. They become friends even though dwarves and elves don’t go well together. I think that says a lot about their psychological depth……

Of course it is also the basic plotline for a million "odd couple" cop films, buddy movies......This ones short and fat, this ones skinny. This ones Mr confident, this ones Mr neurotic. This ones starchy and set in his ways, this one doesn't mind bending the rules to get his collar. And ad infinitum.

I guess you could therefore call it an archetype, though I don't remember them being deep.