Why was the Dungeon of Dorukan so easy?

[pwning doodes]

Looking back on it, it seems strange to me that the defenses for Dorukan's gate could be overcome by a party of low level adventurers. A couple hundred of the minions in the dungeon were brought in by Xykon and not part of the initial defenses. Other than the challenge Xykon provided, the protective measures keeping the gate safe were pretty weak: a Cloister spell, a dungeon full of low-level monsters, one secret door, and a single sigil that could only be touched by someone of pure heart. The path to the gate goes through "many dangerous areas", but it seems the most dangerous of these is the Corridor of Very Toxic Sulfur Fumes, which posed no problem at all to our heroes (or the teenage goblins). Even the elemental corridors from the Linear Guild arc were only to guard the talisman, not the gate. Compared to Soon's walled city full of paladins, Lirian's magic-sapping trap, and Girard's wily illusion pyramid, the Dungeon of Dorukan is downright pitiful. He was an epic-level Wizard, right? My only explanation is that Rich didn't have the gate theme or the Order of the Scribble fully thought out back then and it was just supposed to be a generic dungeon for a low-level party. What do you guys think is going on?