A feature that would be nice to have would be a collimation tool that can show adjustable concentric circles and adjust focus in/out to aid with collimating reflecting telescopes. It could have two modes, collimation and star test.

The collimation mode could work something similar to what is provided here: but using the hardware we all already own.

The star test mode could focus back and forth between inside focus and outside focus, showing the same star side by side at each focus point. First you would go to your "good" focus position, then focus in by a configurable number of steps, take a subframe of the star, focus out the same number of steps past "good" focus and take another subframe. Then show them side by side to compare.