Is this a case of Developer Spite?
The quest is now difficult enough(part 5) that a party with the gear from the quest is required to complete the quest. Congrats on flipping the bird to new characters, and especially, new players.
Please stop tweaking things when you fix an exploit...
Players: Modify your strat! At least 4 clerics are necessary, and make sure your tanks are TWF Evasion Barbarians with dual Mineral 2 weapons!
As for those of you that bring in a party of all Ranged Rangers, you are doing it right. That seems to be the only way to beat him now(again).