Quote Originally Posted by Contrast View Post
Why can only level 20 dex based character whose focused on training with a bow attack 8 times in a round (a fighter) while another can only attack once (a rogue)?
Because one focuses his training on speed, while the other focuses more on accuracy.

Why does a rogue always strike for substantial damage only when he's hidden or an enemy is standing next to his opponent, can't he get lucky?
He can. It's called critical hit. Also, he could have any other source of advantage than being hidden, or be a swashbuckler.

Why do PCs sit there and watch enemies stab their unconscious friend, only leaping into action when its their 'turn'?
They don't. Turns and rounds only exist for the player's convenience, in fiction, the actions are simultaneous.