If your dribble speed is above 90 it could make up for a poor dribble acc, but in some ways dribble acc is more important imo.
Not only does it make it harder for defenders to strip the ball from you, but it changes the distance the player touches the ball with each dribble. Higher dribble acc means you touch the ball more frequently, and that you knock it ahead a smaller distance, which means that you can do more moves, especially in tight spaces around the goal area.
It also makes the 90 degree turn more effective, because you can pull it off at regular pace almost any time you want. If you have a low dribble acc, you might not be able to turn when you want to, because the ball is not at your player's feet.
One thing to consider, however, is that a higher dribble acc actually makes your player slower when sprinting with the ball. If you up your dribble acc, you make more touches, which means you run slower from A to B (laugh at me if you will, but I did some tests with timed races in training mode to verify this).
Bottom line - I recommend both. If I had to choose, though, personally I put more on dribble acc. I'd rather have a player who can dribble well, then one who always burns by everyone. It's a bit less cheesy and more realistic imo.