I have not been to MN tax court, but I do have the same impression that others have given you on the matter. From a practical standpoint I would encourage you to consider the time and effort you will need to put and the potential return that you would garner from those efforts. Even if you are successful, you stand to only recoup a couple hundred dollars from the time spent. Given that my recommendation is to wait for the process to come about next year and let it be what it is. You may see a proper reduction without any work what-so-ever.
From a purely emotional standpoint I can understand and agree 100% that it is wrong for you to pay more taxes than the home is worth.