[featureX] is usually too powerful, it surely would be abused extensively, which would make developer's life a nightmare, unless there is only one developer and whole development takes no more than a couple of months.

This doesn't say much about why syntax extension is too powerful, nor how that would lead to extensive abuse. Well, "too powerful" or not, meta-programming should be more easily available at least at some layer of language development without having to resort to hacking the compiler.

-- Dan Burton