Matteo,
please give some details which of the path you think still exist. I've been there some days ago and I can tell you, they are not existing.
In my opinion, OSM shouldd not be a copy of an official map, that has maybe some of the paths, mapped long time ago.
Setting these actually non-existing path to just not visible is in my opinion not a suitable solution for path in steep mountain regions, as is could result in dangerous.
For example, have a look at way/293470350
Is has been marked as bicycle=yes even thogh a real good mountainbiker would hardly ride that way.