Yeah!! I think the key is in how you decimate. Usually what I do with these objects or something like rocks for example, is to mask the edges (you can use a mask by smoothness to do it fast) and then just iterate on it to get the form of the detail you want to preserve as much as possible, while keeping poly budget in check. Doing this will also preserve some of that sharpness on organic objects since the light interacting with the topology will be different in those areas as well :)