I too would like to express my strong support for this proposal, and in addition, I must say that I'm extremely surprised by the concerns and opposition expressed by others.
For libraries which outsource authority control to a vendor, the local maintenance resulting from the changed headings would presumably be done automatically through the periodic updates.
For libraries which handle their authority control manually, the implementation of this proposal would have a more pronounced effect on their catalog maintenance. Such libraries could certainly choose not to change their headings in bib. records to match the altered authority record.
Frankly, I think the benefit of having death dates in headings is well worth any extra work caused by changes made to the headings in the national file.
Cataloging & Metadata Services Librarian