Hi,
These days I only use a single class and the rest of the points are in traits and disadvantages. Be careful with disadvantages though they can ruin your late game.
Nothing in stats! Because stats are easily increased through courses, books, actions. events etc..
Although be careful with minor stats as some skills require specific stat values or above to be able to use.
For example I think that to repair your hulc armor requires at least a 50 in blacksmith. which you may not have if playing a slaver.