Why was the Dungeon of Dorukan so easy?

[Metastachydium]

Lirian's defenses seemed to prioritize making the gate un-capturable as it would require keeping the treants alive and immobilized before they could act. Though I imagine TE could have pulled that off. I guess the thought was that by the time a powerful threat bypassed the other defenses, the treants were supposed to break the gate, maybe.

Which is weird, since when Lirian's Gate was set up, Lirian had no reason to believe that their spell can be corrupted via something like the Dark One's Ritual (and I'd assume that they would have come up with some other way of sealing the Rifts were they to realize that Gates are unsafe), and therefore one would think that her priority should have been keeping the Rift sealed.