The GNU copyright contributions are still harmful. They've caused forks and driven away potential contributors. The kernel has no copyright agreements but it's been more useful in enforcing the GPL. GCC could still be relicensed by using the GPLv2+ license. If you need to change the license entirely, that's maybe trickier, but lots of projects have relicensed by asking individual contributors. Btw, the people who died can't sue you.
So not needed and harmful is probably an accurate description.