Focal point: more control?
There's no way of doing that natively. 

When you're cropping an image with Craft, it zooms in as little as possible.  So, if you have an image that's 800x600 and you crop a square at 500x500, Craft won't zoom in at all.

When cropping is finished, the next task is to get the focal point as close to the center of the final image without crossing out of bounds.

Consider if Craft tried to put the focal point in the center no matter what. If the focal point was 100 pixels away from an edge and you wanted a square of 300x300, that would result in 1.5x zoom which would be a less desired outcome for many people.