I think the addition of the Default Contributor License is great. Contributing to an open-source project should really implicitly mean you agree to license the contribution under the same terms as the project (and are able to do so), but sadly that’s not the case.
I’m honestly surprised that this point isn’t addressed better by popular OSS licenses. I can understand the need to modify things in some way if you’re dual-licensing or something of the sort, but it seems like the bog-standard licenses could provide an out-of-the box contributor agreement.
Overall I was impressed by how clear and easy to understand the whole thing is. No mean feat considering the kind fo contract that’s embodied in that verbiage.