On the buggy knock-forward problem, wouldn't it be possible (caveat, I have no idea how programming works, you use a keyboard with just a 1 and a 0 on it right?) to have it always calculate the knockback direction based on where the player is, instead of worrying about where the spell is coming from? Or whatever it does now, it's kind of hard to tell. This might look odd in a few scenarios, firing a spell while falling and then having the angle to you change when it hits the monster, but I think overall it would lead to better, more consistent behavior. I know in Valley 1 I died a few times due to a whip or a melee range spell deciding to bounce a monster right into my face.
Whether knockback is kept as-is or relegated to just a few specific spells, having it always knock them in a direction that could be described as 'back' would be an important property, one would think.