MILAN — When Simone Bellotti started work at Jil Sander, he found himself confronted by an existential challenge. He worried about adding something to a brand which has always been about taking something away. He didn’t have this problem during his previous situation at Bally, where, in barely two years, he made his name with his strikingly idiosyncratic world-building. But it was easier there. When fashion thought of Bally, it thought of shoes. Jil Sander, on the other hand, comes…

