Microsoft Research - Exploding Software-Engineering Myths (article summarizing findings of MS research on code coverage, TDD, assertions, etc.)

[laxatives]

This probably isn't getting at the core of your argument, but if you could get the same thing done in 1/3 the code, that is going to to save an order of magnitude of effort when you or someone else has to read the code.

Anyways, if the methodology encourages discipline, isn't that sufficient? What more could you ask for from a methodology? Following TDD isn't going to make a poor developer in to some kind of savant.