@Kaldraydis, I’m afraid this isn’t just about moving files. I was halfway through TFT when this forced upgrade hit, and now the game has been completely reset. The only sign of a save file now is in ~/Documents/Warcraft III/BattleNet/#######/Campaigns/Classic/Classic.w3p, and this file is pretty clearly a new campaign save.
I’ve searched through the Warcraft III installation folder, and it has been cleaned of anything save related. At least the update could have left the original data alone as a backup.