Expertise will be installed on Tuesday.
-Captain Kirk
This game is far away from release. I was at first very disappointed that Larian didn't strait away commit to the RAW, as well as frustrated for them that they were creating so much work for themselves by not trusting the tried and true.
I have to say that I am impressed with their steadfast dedication to make this game work. As they cross some important progress lines...like level 5...moders will be able to polish their class mods.
My guess would be that the programmers simple haven't tackled expertise yet...or how to give double advantage (Elvin accuracy)...or any number of things.