I suggest that the more stiff the sole the more it is likely to slide, regardless of the rubber. So a model ideal for winter use with crampons has a disadvantage.Another boot I tried years ago had a built-in curve, to help with a more natural walking action. This meant that only a limited section of the sole was in contact with the ground especially if it was level. The more flexible the sole the more it conforms to the ground. At the risk of boring everyone, I do find that Inov-8 footwear has the right combination. A pair of poles also helps.
Interest comment about walking action. Watching the occasional film of people walking, many seem to have a very positive heel strike, sometimes on the rear edge of the heel, which would obviously make a slip more likely. Checking myself, I realised I walk with slightly bent knees acting like springs and from the hip rather than swinging from the knee - developed over the years without my realising it. So I am effectively flat footed, with a full length foot plant and my body weight is almost vertically above my fore foot not behind it.