Sleet Storm - 3rd level (and it makes a terrain effect that makes people fall prone, so I'm flabbergasted that Larian didn't put this one in already... it's right up their alley.)
My druid got Sleet Storm as a third level spell, not sure what other classes should get it?
Sorcerer and Wizard as well. I've just checked and they all do have access to it.
Which is worth checking, I'm still waiting on clerics having access to Calm Emotions.
I don't know if there are other instances of certain spells not being available to certain classes when they should?
