My advice on implementing stuff in C:

I think I agree with michaeljt's comments more than yours. Most of the things you complain about are either very rare (virtual base classes) or provided by every other OO language (RTTI) *and* rare in C++ code.

The overloaded function resolution rules aren't all that bad... however, the name lookup rules all added together are fiendish: add 'export' and I can understand people's brains dribbling out of their ears.