Does anyone have any comments on this? Support or objections?
I don't think it is cut and dry. It is a case of consistent behaviour versus implementation defined behaviour. In the past I've found it suited myself too to get rid of the catch all clause so I'd probably come down in the get rid of it and leave it implementation defined. Exception safety across threads is a point of contentious design and best left to the user to deal with it by specific design I think.
I think I'd come down on the other side: this isn't a minor change, it's a complete change of semantics and we should be very careful about such a change. With most of the compilers I use an uncaught exception thrown from a user thread will terminate the application, which may be what you want, or it may not: but it sure is drastic! You can always trap uncaught exceptions yourself and call abort (or whatever) if that's what you want. The debugger I use will also let you trap all thrown exceptions if that's what you want, whether they all do that I don't know. Also 2c worth, John.