Just a short and overdue announcement. The Import Tool for the RS1-Songs should now work for EU PS4 users. Rocksmithians have been reporting that the purchase of the tool on PS3 even transfers onto PS4.
By now the gap of missing content has become a lot smaller. Check out R2_'s list of remaining issues on the Ubisoft forums and let him know if you encounter any other issues or if one of these appears to be fixed by now.