I appreciate the defense, but to be fair I did bring up HP spells in a (small) part of my post:
Saving Throw Spells/ HP spells: less proportional damage (nerf) and no effect from height/lowered AC= 1 net nerf.
HP based spells have been indirectly boosted, now they have a fixed value, you can easily increase this value to the maximum possible cast (which will be a huge buff)
From what I can remember, Larian mentioned that the current difficulty level is closer to hard than normal.
At higher difficulty levels, mobs will likely have more HP.
This is true, HP spells (different than Saving Throw Spells) now do have a fixed value. And I believe that the value chosen for Sleep (28HP) is actually above it's expected value when rolling (5d8=22.5)? But it is still a nerf.
Advantage basically increases your chances to hit by ~50(?)% (chances of rolling a 10 or higher go from 55% to 80%). Thus, an equivalent increase in sleep would be 22.5HP->33.75HP, more than what is given.
Also, goblin HPs are generally increased by ~50% or more. (7 HP goblins to 12HP is a 70% increase). Again, this overwhelms the slight increase in Sleep's HP