Completely agree. I was about to write something along these lines but you did a great job. :-)

In a decade using C++, I haven't encountered these problems. I never use exceptions and I do exactly what you suggested in #2: if construction can fail, have a factory method and a private constructor (I use a simple ValueOrError<T> type, rather than optional<T>, to be able to communicate information about the error, though: https://github.com/alefore/edge/blob/876c4328610262b11fda553...).

Cheers!