I have an idea about this interesting mod from some of my references:

Level 1 is Beginner (Basic psycast manipulation; Yeoman-level)

Level 2 is Intermediate (Advanced psycast manipulation; Acolyte-level)

Level 3 is Advanced (Complex psycast manipulation. Generally large area of effect; Knight/Dame-level)

Level 4 is Expert (Larger scale complex psycast manipulation; Praetor-level)

Level 5 is Master (Builds upon Expert-level Psycast by increasing its effectiveness. Usually spells that affects the weather; Baron/Baroness-level)

Level 6 is Ultimate (Further enhances the scale of Master-level Psycast and possibly continental (tile) scale psycast or disaster; Count/Countess-level)
*Note: since dev said that 5 level is already enough to create good ability tree, so this level could be hidden/secret abilities which obv hard to get.

Your thoughts are welcome...