Don’t get me wrong, I welcome comaintenance projects. But it does make it harder for people to assess the quality of maintenance.
I raised some of my concerns here: Introduce Haskell Party proposal by bergmark · Pull Request #12 · haskellfoundation/stability · GitHub
I’d personally only use such comaintenance if I could define a custom patch policy (e.g. no feature patches in my absence, or no major refactorings). But at that point, I’m probably better off managing my contributors directly.
I don’t have a definite answer on the topic as a whole, but wanted to share my doubts.