Schalke 04 has one of the prettiest and most clever badges/logos in the world. With very few lines and shapes it references the name of the club, the place it belongs to and the mining tradition tighthly linked to the city of Gelsenkirchen. (Just in case you don't know, the "G" hides a hammer, i'm saying this just in case you haven't noticed... I can't be the only one that looked at this badge dozens of times over the years without noticing it.)
Such a clever badge needs only minor adjustments, mostly related to how some lines, shapes and spaces help define others. It creates a slightly cleaner look, which - in my opinion - is the only change it needs.
