Pathfinder is a very complex rule set and Kingmaker/wotr expect a very deep knowledge of the rules to enjoy the game. If you create a char based on assumptions from a role playing perspective, the result will probably be bad game mechanics wise. The game tells you the numbers of your char, but it requires some experiance in order to tell if those numbers are good or bad. So the character screen tells you that you have lv x, AB y and AC z, but is this OK when you want to fight demons, especially when enemies in the game have very inflated stats compared to PnP, even on normal where the game tells you that enemy stats are lowered?
New players have to look in the internet for forums or guides. You find a lot of them, some are good and some are bad. But new players cannot tell what is what. If you read a guide and you understand why it is good or bad, then you do not need a guide. Some other guides are good but they are based on assumptions that are clear for expert players but new players do not know this.
A random example I just made up: Many guides could tell that a martial char should take shatter defense, but not all of those guides tell you that this has only an effect when you have a melee char with power attack/cornugon smash/dreadful carnage and high persuation skill or a bard that uses one specific song.