First you have to determine for yourself what "horrible blade geometry" means. Perhaps it's a perfectly satisfactory edge for what Tom Brown needs it for. If you want it thinner, for example, then simply resharpen it at a more acute angle.
Depending on how much thinner, you may want to use diamond stones to reprofile the edge, but this has the drawback that you could overdo the job. Be sure you know how to use your sharpening equipmnent by practicing on a cheaper knife.