dribble speed and pace are quite misunderstood stats really. here's how i always thought it worked.
pace is the player's top speed, and acceleration is how quickly they can reach the top speed from a standing start. so far, so obvious. but when you're on the ball, the dribble speed stat acts like a percentage of pace and acceleration as far as i know.
say you're controlling a player with 80 pace and acceleration but a dribble speed of 60. that means he's never going to be able to get past a maximum speed of 48 (80 x 60%) when he's dribbling. so someone like cristiano ronaldo should have a stupidly high dribble speed score and that's what would set him apart from less good wingers.
when the player's chasing a ball the dribble speed stat isn't used so i usually use the R2 + change direction to push the ball past the defender and then run onto it, if there's space behind them.