Wit (WIT)
WIT is the value that expresses how quickly a character can think and his/her ability to make things happen. As INT is the value that demonstrates the level of understanding, WIT is the value that shows the character’s ability to make things happen and the character’s mental spontaneity. This value has an effect in the following ways.
Exceptional damage probability: Exceptional damage can occur at a certain low probability when casting damage magic and the higher the WIT value, the higher the probability that this exceptional damage will occur.
Magic casting speed: If the WIT value is high when using magic, the magic can be used more quickly.
Resistance to abnormal conditions: WIT has an effect on one’s ability to avoid various kinds of bad abnormal conditions. Abnormal conditions a character doesn’t succumb to easily when WIT is high include curses that lower ability values, mental abnormalities (such as Hold, Silence, Sleep, Fear), paralysis, HP reduction magic of the four elements, MP reduction magic, HP recovery speed reduction, and magic that increases the delay for reusing skills and reduces heal effects.
http://www.lineage2.com/news/chronicle2_05.html
I can't recall any update since then, that modfied the WIT bonuses.