The spawn rate in this version is extremely high for most hostile mobs- spawn rates between varying difficulties seem to be the same. There also seems to be huge clusters of the same mob spawning in a given area, such as 6+ creepers suddenly spawning in a small dark space not far from the player.

The clearest example of this is in the Soul Sand Valley, where Ghasts spawn at such an absurd rate that even on Easy difficulty, it borders on unplayable. At no point there isn't a group of Ghasts in your immediate vicinity shooting at you, to the point where they will spawn immediately in front of you if there are none.

In the off chance that the Ghast spawn rate isn't a bug, I'd still strongly recommend at least lowering the spawn rate for Ghasts considerably, it simply isn't enjoyable to be spammed with high-knockback projectiles from every single direction.