Last time I was training for classics in flanders with cobbles. However it is difficult to find cobbled sections you do not know. However, most cobbled sections have a Strava segment. It would be nice when segments can be categorized and marked as cobbles for instance. Other categories could be MTB single track, gravel roads etc. where I live we do not have any hills, so this would be some nice additional information regarding segments. Off course it should be possible to search for those different type of segments in the neighbourhood or when creating a new route, so you can create your own local Paris-Roubaix or Strade Bianchi or off course you can exclude certain segment categories from your route if you do not like cobbles etc.
Another suggestion would be to select different parts when using a bike. I have different outer tubes and wheels, but I cannot select them separately. However, I would really like to know how many kilometers I used every item.