At present, we have lots of people with CVS access, and it's up to each developer to decide when they commit to CVS HEAD. For example, if I don't hear back from Brion on the namespace changes soon, I'm going to give them a final look and merge them into HEAD. Brion usually _does_ react quickly to problematic changes there .. ;-)
Then there's patches by outside contributors without CVS access. I think these can be dealt with by allowing anyone with CVS access to handle them, since the assumption is that people with CVS access are reasonable. It may be desirable for some developers to take on a formal reviewer responsibility, so that people can contact them explicitly.
And then there's code that is in HEAD, but it is either an extension, or it is a site-wide option. In those cases, someone has to make an explicit decision that the code is ready for use on the Wikimedia sites. I believe your recent extensions, as well as the old Validate code, fall into that category.
In those cases, the general procedure tends to be "Wait for Brion" or "Bug someone on IRC", but it's not immediately clear what the responsibilities are.
It may make sense to let Brion give some people a formal "code activator" privilege. These people would be allowed to enable code on the live sites. Bugzilla could be used to keep track of who is going to review and possibly activate the code, if anyone. If there are no volunteers, and the code is generally deemed important and useful, the responsibility would fall back onto Brion.
This would let you know that someone is indeed going to review your code, and if they decline to integrate it at the present time, will give you feedback on what needs to be changed.
What do others think?
Erik