Do you not require your Dev's to report in on what bugs they fix in a particular patch, or are your managers just too lazy to publish patch notes?
Sorry if that sound's bitter... but I don't get a whole lot of gaming time, and what time I do get the server has been down... and never an official word on why or when it will be back up (ok, sometimes you do - but not the last few times), and now we get another patch without any notification of what's in it.
Is it that important? No... not really. Its not like its optional lol, but your customers like to know... and such a simple thing would go a long way for me and many others to ease our frustrations about the state of the game servers.
Here's a suggestion: Have your project manager spend 10 minutes and put together patch notes before releasing a patch. Key word: BEFORE. Its not that hard, and its not that time consuming (or if it IS that time consuming, you need to ask yourself WHY - it should be the job of each developer to add to the patch notes as they log issues as fixed - a very important part of ANY quality assurance).