Well, the importance of knocking shouldn't be underestimated. It is not done just to compress the fibers - that is just one aspect of knocking. The other one is breaking the handle. A new bat has a very stiff handle and the knocking process loosens the twine enough to give a vibration-free performance. That's why the feel of a knocked bat is softer than a new bat. People say knocking reduces vibration and the reason is your handle becomes slightly more forgiving for a mistimed shot.
Also, with compressed fibers, the seam can't cut through the blade. To reduce the knocking time, I generally work on the edges and toe and them apply 2/3 scuff sheets and take it into the nets. As the bat gets older, I start removing the sheets. By the time the second sheet comes off, it is ready to go into a match against a new ball. Getting the edges and toe compressed is very important.
If you further want to reduce your work, you can lay your bat on a very thick towel and then strike it with mallet. When you generally hit it with a mallet, the bat swings back and it causes loss of power during knocking needing more impacts to achieve same amount of compressing. If you eliminate the back swing, your knocking time gets reduced. The downfall to this method is if you knock it too hard and too much, you may lose some of the spring, so be a little careful and don't overdo it.