Arc was criticized when it came out for being basically a few macros on top of Scheme. I don't think that's a valid criticism. I don't know if Arc is the hundred-year language, but whenever the hundred-year language does come out, it might easily be some carefully-chosen macros on top of Scheme, macros that help write other useful macros.
I mean, arc hasn't really 'come out,' has it? It's still being worked upon... the front page of that site specifically says the only reason there have been releases is to improve the language.
