From a pure meta-programming perspective, I guess the only real addition is variadic templates. However, there is the problem that they're fairly limited and that one may not expand them as the arguments of a non-variadic template.
I thought that was allowed. At least, GCC supports it since 4.7, and its error message for it in 4.6 was
"sorry, unimplemented: cannot expand 'Args ...' into a fixed-length argument list"
which suggests the feature is not an extension.
The relevant GCC bug report is PR 35722 [1]. It is mentioned there that the change that made this valid was the incorporation of N2555 [2]. Note in particular the sentence in section 14.3 paragraph 8 that was struck. Regards, Nate [1] http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35722 [2] http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2555.pdf