I had the original 4th edition version and then purchased the upgrade pack. I also updated my game board by downloading, printing, trimming and carefully pasting the revised scroll text available on the FFG website on the appropriate spaces. The patches ended up matching so well with the printed board that I have to run my fingers over it to feel for the raised surface of the stickers to figure out which spaces have them.
The game plays very well with Fate, though it does certainly make toads much more scarce; I've yet to see any in the first few games I've played since the upgrade.
I also acquired the Reaper Expansion at the same time. It includes some nice new cards and characters for the game. And although the Grim Reaper is an ominous presence on the board, he has yet to have any effect during any of our played games seeing as how he rarely if ever gets close to any characters; he simply isn't moved often enough for it to occur.
This past weekend I also bought the Dungeon expansion and gave it a whirl. It's much as I remember it being in the 2e version of the game. The general consensus is that's its a meat-grinder with plenty of challenging monster encounters but few payoffs. Still, two of the players spent a fair bit of time in the dungeon exploring its halls; though neither of them won in the end. So, all in all, a fun though challenging addition to the game.
During this latter session, the Witch appeared on the board and, with a few fate tokens in reserve, she isn't the toad-turning terror that she once. In fact, with the significant bonuses she offers to those who encounter her, I spent a fair amount of time hovering around her space so as to meet her over and over again. In the end, I never had to spend fate on her, got a significant power boost and ended up winning the game. So yeah, toads are indeed much rarer thanks to the fate mechanic. One idea might be to allow competing players to spend their own fate tokens to counter the fate token expenditures of unfortunate players. 
