On the triple-or-value front, the main case I see for considering the "you don't need exception state triples any more" argument already lost is the fact exc_info still returns a triple, and __exit__ methods still accept them as unpacked arguments. The C level exception handling APIs are also all still exception state triple based. In this view, __traceback__ is primarily about accessing *chained* tracebacks, while the top-level APIs still focus on exception state triples.

This perspective also has the virtue of confining use of the Python 3 only exception traceback attribute to code that is taking advantage of a Python 3 only feature (i.e. exception chaining). For chaining independent exception state handling, working with exception state triples then remains the "one obvious way to do it", a way which is conveniently also source compatible between Python 2 and 3.