first of all I know that there are a lot of similar questions about this topic but it's difficult to see if my concern was already processed.
At the moment I have an accept rate at Superuser under 80 and it's getting worse because you could say you will be punished when you ask questions where almost nobody has an answer. Sometimes you only get one answer which didn't solve your very special problem. So you can say the more difficult your question will be, the less is the chance to get a satisfying answer and hence you accept rate falls more and more. You have the possibility to delete you unanswered question to save your accept rate, but that doesn't help other people with a similar problem. Or you answer your own unanswered question to not lose much more of your accept rate. Moreover you prevent people of posting possible helpful answers.
I have a proposal for that problem. The accept rate should not be decreased as long as you write comments to every (unsatisfying) answer (to give an overview why this solution didn't solve your problem). So if you have 3 answers, and these answers didn't solve your problem, you could write at least one comment to every answer. That shows that you are still interested on your question and it also shows that you did not leave your question unanswered. This method would be very fair to everybody. Wouldn't that be possible?