It’s not straight in relation to world origin. It’s straight in relation of the chain of bones. A good example is the way you had it setup would be perfect for a bow legged person, because their knees do point outward. I choose to align along the world axis instead of aligning the shin to the thigh’s position, because it was easier to describe in text. Bone Roll and the alignment of the bone’s axis are very important in getting the expected movement while making it intuitive for animators. These become even more important when you add IK, because Blender relies on this to calculate how the bones should move/bend. As for Realistic, the best way is to break it down to parts and keep testing over and over as you go. I like to start at the hips and go thru the leg first. Then the basic foot. Then the body. Then the arm. Then the basic hand. Then go back to the foot and add advance features like foot roll. Then advance features of the hand. Then the neck and head. Then lastly the eyes. I’ve just started learning facial rigging so I’m not as adapted on that, but I can still trouble shoot problem in this area.
