would be not to give any extra points, but to give a new Skill/Spell for each class.
A unique Spell/Skill that you can skill only by reaching Dual 5, and let the stats the way they are now (max. Dual 4 stats).
Dunno at which point the GM's can implement this.
give priest ultimate buff spell, sfd + z with the same spell + remove curse + speed increase xD
See, this would be an awesome spell for a Priest, that he could archieve by reaching Dual 5.
The wizards would get the increase Magic the GM suggested, need to think something good for Thief/Archer/Warrior tho.