Avoiding projects without copyright assignment... well, a mixed blessing.
Copyright assignment discourages contributions from all but those with the most serious need to scratch their itches, because it erects a barrier - at the minimum it's extra paperwork, at the other end, you may need to get executive approval from your boss to release the copyright on "your work".
It also creates paranoia. If you assign the copyright for your work to a company, nothing stops them re-licensing that code however they like. They can take the code private and profit from your efforts. No-one likes to be taken for a mug.
The converse, projects composed of mixed copyright code find it harder to change license - which means they are more likely to remain as open as they were before.
When LibreOffice forked from OpenOffice, it took most of the core contributors with it - and ditched copyright assignment. It's by far the more vibrant project.