Just don't give time out to let the batter step out of the box every pitch.
New rule, you get one timeout per at bat. Here's all it would take:
1. The batter steps out thinking he's getting time, as usual.
2. The ump doesn't give time and instead signals the pitcher to throw.
3. If the pitch is anywhere near the plate, it's called a strike.
4. The batter and the manager get tossed for arguing ball and strikes undoubtedly very loudly and demonstrably.
I guarantee that no batter will ever step out of the box again.