The idea that the maintainer must create the PR is fighting the optimized github PR flow. Github and PRs process is optimized for letting everyone contribute from "their" fork while still protecting and putting process in place for the "upstream".
Why not use github to assign maintainers to each package or filepath and then let contributors submit their own PR to edk2 after the mailing list has approved. Then the PR has a policy that someone that is the maintainer of all files changed must approve before the PR can be completed (or you could even set it so that maintainer must complete PR). This would have the benefit of less monotonous work for the maintainers and on rejected PRs the contributor could easily update their branch and resubmit their PR.
