Quote Originally Posted by Ultimatecalibur View Post
No, its to avoid having mechanics unintentionally cheesed/broken by terrain.

Dhorme Chimera is a perfect example of this happening: Pulling it up the hill allows characters to have a far easier time avoiding several of the AoEs without even moving.

It was possible for ranged dps and healers to dodge Mortal Ray(which gives the instant kill Doom debuff) in the Teratotaur fight in Sunken Temple (NM) by climbing up the mount of sand in the room negating most of the fight's mechanics.
The original arena for the T5 Twintania fight had an uneven floor and players figured out how to stand in a pit near the arena wall to trivialize the divebombs mechanic. Later on SE made the floor in the arena level but the players already knew where to go and the mechanic was not altered as Second Coil had been released at that point.