This would be a fantastic feature, especially for imaging the moon during daylight or twilight when stars are unavailable.
Because this is unavailable in Ekos, I routinely switch to TheSkyX *just for autofocus* and then switch back to Ekos. TheSkyX "@Focus3" uses a gradient (contrast)-based focus metric that produces razor-sharp results by focusing on the Moon.
Implementing this in Ekos would require an alternative focus metric but (in my naive expectation) no new code or logic for moving the focuser, computing the curve, solving for the optimum position, etc.
"Sharpness" metrics are well-studied because it's the basis for autofocus in conventional photography. Daytime photography (eg, in your phone) can't use star sizes. The kind of focus metric required for Ekos to autofocus on the Moon is in fact the metric used by virtually all autofocus logic in the world.
The math is well defined and there are gradient libraries available in many languages to make it fast and reliable.