Personally, I frequently fall into the uncommon cases. I realise that that makes me uncommon, and don't blame Google for doing what works for 90% of their users. However, for me personally it's not a great experience anymore, I am irritated by auto-correct far more often than I am helped by it. As someone who knew how to use the synonym operator, I never felt that I wanted Google to do this for me automatically. Now it does, frequently, and in some cases using the exact match operator is overriden by Google deciding to match synonymns anyway. At this point, I can't even control what I'm searching for.