Berserk is weakened to 50% damage (+no bonuses for spellcasting). Similarly, Subjugation (reduced to 50% initiative without spellcasting bonuses, except for duration).
Confusion is available at level 1, but its duration is fixed at 1/1.5/2/2.5 rounds (depending on the skill), and it won't be possible to keep it active for too long.
For now, I doubt that Confusion at level 1 for 2 mana is more powerful than Weakness at level 2 for 3 mana (roughly speaking, it reduces damage by 2 times for 2/3/4/5 rounds), since Weakness is more versatile (effective against melee units as well).