I don't see why it may fail to integrate. Declare Pin as !Move and... thats all? I mean, there will be issues, edge-cases because it is just how these things happen, but still I don't see any fundamental issues with continuing to use Pin.
Pin applies to the pointer, !Move applies to the pointee.
Give it some time and see how people will use it and problems emerging. I do feel that this will stay.
Like others said, Pin is incompatible with these semantics. Some people argue, though, that we need both (basically because pinned types can be moved before being pinned).