(2.3) I'd prefer has_xxx over has_operator_xxx because I think that operator names xxx can stand for themselves without an "operator_ reminder" prefix. The has_operator_ prefix is lengthy and introduces unnecessary redundancy.
Hmm, I'm not sure it is completely redundant - I prefer long_descriptive_names to short_cute_ones because it makes the code easier to understand - even though it result in a touch more typing.
(6) I'd be nicer if we had quickbook docs, but as Frédéric has pointed out he integrates into the the prevailing style of the "mother library". Still it may be nice to take the opporunity to update the whole type traits docs to quickbook style. But this is a lot of work of course and goes beyond the scope of the extension.
FYI All the type_traits docs are in quickbook format already, it may not be obvious though if the sandbox versions aren't picking up the usual stylesheets. John.