Ugh, why the gratuitous dig at Guido? I think he's done a fine job leading Python, and I've found the Python community to be particularly friendly. Sounds like there's some beef here.
As far as I'm concerned, when he says, "The one issue on which TCO advocates seem to agree with me is that TCO is a feature, not an optimization.", it's complete bollocks. When your program blows up because you don't have TCO, that's a semantic failure--not a lack of a little optimization.
I think that's what he was implying. As in, TCO is a major decision that goes into a language design, not just some sprinkling of compiler optimizations, usually.
I'm claiming that using self-recursion just makes sense. The inability to have a recursive implementation of fib(n) is a loss in both expressiveness and readability. Recursion is fundamental to computer science, and is often the best way to express many types of operations. So, in my opinion, if Guido really wants Python to be simultaneously readable, expressive and pragmatic, TCO is necessary, because recursion just plain rocks sometimes.
