I have played NWN2, but only OC, MotB and SoZ and I do not know the PnP rules.
Why do you say warlocks and other arcane casters are bad?

Warlocks can use a few spells infinite times and their eldritch blast gets 1d6 damage every odd level. You can upgrade the blast to cause AoE damage and cause additional damage or cause additional effects.
It is a touch attack and it can ignore spell resistance (the SR part is complicated, but it can be ignored).
So they do exactly the same as kinecticists in PK which you called very powerful.

Sorcerers are considered one of the most powerful classes in NWN2.
All of them use the arcane scolar prestigue class for more meta magic. The default epic caster is 26 sorc, 3 blackguard and 1 lv in another class.
The epic version can cast all spells in plate armor and shield, the normal one can still make himself immun to most effects and disable or blast all enemies.

groovy Prof. Dr. Dr. Mad S. Tist groovy

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