They should just make it like in D:OS1 were better skills need a certain knowledge of a class. In D:OS2 you had max of 15 skill points per class (1+2+3+4+5=15), you needed them to learn all the skill and master the strongest.
In D:OS2 you can even learn the strongest skills (source) with only 1 point put into a skill, you are only limited by source and memory, wich is a heavy dumb down from the previous style. D:OS2 feels like an oversimplification compared to the first.
