I think part of the problem is that this project is still undergoing a cultural shift from being a purely internal project to an open source one.
With an internal project decisions are made by a conversation with a few people directly, and it's fair to assume most people will have a good idea of how the codebase works.
With an open source project more discussions need to happen in the open, and lots of times users are not going to be familiar with the codebase. That lack of familiarity requires a community to support things- for example, I never would have been able to submit the PRs I wrote without assistance from @ags131 and reviews from other community members.
I do think the admins are making an effort. Reaching out to the community for development on the Tombstone and Source Keeper functionality features was a huge step in my opinion.
That being said, it would be great if pull requests didn't take as long to process, and if in cases like this PRs weren't closed immediately without a bit of discussion. As long as the admins are still open for discussion I don't think people should be too fixated on what the current status of the PR itself is, and this forum might just be a better place for it.
As for the relatively long process between making a PR and getting it merged I think there's a huge technical burden in the way that we haven't talked much about- the lack of a test suite. I know for my own open source projects I don't even look at PRs which fail the tests, and the projects which don't have tests are orders of magnitude more difficult to manage. This might be an area where the community can step in and help, if the admins can put some infrastructure in place (even a Circle-CI test setup that only looks for syntax errors and code formatting would be great to start with).