The document talks mostly about Mediawiki deployment and Mediawiki extensions, but there are more projects in Gerrit than this. I think it should be clarified whether these policies are to apply to them too and then they need to be written in a bit more generic way or just to "big Mediawiki" (i.e. Mediawiki plus extensions plus puppet, etc.) but not other code hosted on WMF Gerrit.
Topic on Talk:Gerrit/Privilege policy
The scope of the policy extends over all repositories on WMF's gerrit instance. However, there are several bits that only apply to MediaWiki, or only to code deployed on the Wikimedia cluster.
It's intended to apply to all projects that are in WMF Gerrit. There are some bits that are fairly specific to MediaWiki, do you think they should be removed?
FWIW, I initially had the same reaction, many of the arguments surrounding the importance of +2 make direct reference to the particular configuration of MediaWiki and extensions Gerrit and Jenkins setups.
Putting that aside, the section on merging without code review feels particularly prescriptive; however, it makes the point towards the end:
For extensions (and other projects) not deployed to the Wikimedia cluster, the code review policy is up to the maintainer or author of the extension.
I think I would prefer if that were easier to glean from an inspectional reading of the policy rather than a close reading.
Also, it's important to note that self-merge is common in some repositories (integration/config for instance), and there may be differences between projects in what exceptions there are to merging without code review; however, in these projects, +2 is still "a strong expression of trust", only the expectations are different.