I think "cripple" is a little extreme. But I do agree that we need good metaprogramming constructs, and I'm really very interested in that, I'm just not that psyched about some particular techniques.
And there's a lot more opportunities to do metaprogramming now than there were a few years ago -- in part because of changes in the language (mostly Python 2.2), and in part because we're learning better techniques to use those features. There are a lot of avenues for exploration, most of which are probably a bad idea ;) And we have what I'm guessing is the same as method adjectives in Python, I believe at the bequest of Zope people, though it was too late for them to use them -- functions can have arbitrary attributes with arbitrary values (since Python 2.0 or 2.1?) And of course classes have always had this ability. Or maybe you are thinking of something else?