> 2to3 doesn't deal with anything else that has been removed.

That seems a bit odd for me... isn't it the perfect place for that? (it
doesn't even need to change the code for a pass, but it could give the
user some warning about it at that specific line -- maybe with a pointer
to a place explaining why it was removed).

I think that if 2to3 flags it, it can make the porting cycle faster than
having to run the code (and expecting a huge code-coverage) to get those
-- especially as sys.exc_clear is mostly used in cases where you are
expecting some exception... and I believe not everyone gives as much
emphasis for exception cases as they'd for the cases in the 'regular flow'