One doesn't have to look far before he finds a fatal flaw in the commentary. Particularly this:
"In my mind, a language construct is expressive if it enables you to write (and use) an API that can't be written (and used) without the construct." - Neil Gafter
Once more, there is no such construct. All APIs can be written and consumed without language support. Otherwise, Boost would not have had all the new C++ goodies (as an add-on library) before they became part of the language itself. And, of course, one can always put the 'human compiler' to work to produce boilerplate that would be produced by the compiler if the language in question supported the feature in question (if there isn't an add-on library providing the feature in question). One can always do this but the discriminating one tries to avoid it and instead chooses 'expressive' (i.e., conciseness-facilitating) languages. [In the case of closures in Java, one [human-compiler] would merely use one-off interfaces or anonymous classes].
I will take a look at the other links but I gave up on the commentary after seeing such a blatant falsehood.
