The spawn rates of Ghasts, Endermen in the Nether are too high

The number of mobs, mainly Ghasts, that spawn in the soulsand valley make gameplay difficult and slow the game. There can be up to five ghasts at once in a small area and even more once you start killing them. 

On a similar note, the number of Endermen in the warped forest are also extremely high, comparable to the end almost, making the "safe biome" an oxymoron.