I find it ironic that github PR, that are supposed to be here to help collaboration are actually very individualistic in some way.
It really put the burden on the submitter instead on of the group because on how single "threaded" it is.
I would really like to be able to make proposition on the PR as suggestions for the submitter or for the group instead on only having review possibilities or pushing directly on they PR.
PR should be a discussion place, not a submission place.