By adding a new committer and removing the original committer can I effectively change ownership of plugin? I would like to transfer a plugin to a new wordpress.org profile. I am the author.
As of 2015 you can do this yourself, and you don't have to email anyone.
Go to your plugin page (example: https://wordpress.org/plugins/hello-dolly/ ) and click on the ADMIN button on the right hand side.
On that page, add the new person as a committer and remove yourself.
Then update your readme and plugin files to point to the new USER ID and check the code in. You do not need to bump your version numbers.
It will effectively change the ownership, though it will still show up in your profile if your old username is listed as a contributor, and may still show up in your profile if your old username was the creator of the plugin. To fix the second part, email firstname.lastname@example.org and Otto42 or I can re-assign it.