I will just leave this here based on what I felt is the best during the icbt2. I played as a Wiz 3 Ele 3 at max level in icbt2, and went for boss hunting frequently.
Reflect Shield is useless, you don’t need a single point in it. That slight damage reduction will not help you against thousands of damage dealt by the monsters (unless the monsters are nerfed after icbt2).
You only need Earthquake at level 1. The damage scale is terrible. What you need from Earthquake is the disable.
Sleep should be maxed, every extra second of disable is just good. There is no arguing this. Do take note you can instant cast sleep by releasing it instantly.
Energy Bolt, while the damage scaling seems bad, the reason why you level it is to reduce the cast time to use the level 1 Energy Bolt. At high level, you can quick tap energy bolt to instant cast it.
I left Lethargy at level 1 to utilize the strike damage attribute, and double damage on earthquake at early game.
You can interchange points between Surespell and Energy Bolt to whatever value you are comfortable at.
Forget about sp issue. Once alchemist exist in this game, you can buy concentrated sp potion easily which solve all the sp problem.