I guess coyotes are infinitesimaly easier to call in at night vs day.... but we have had great success calling them in and killing them in daylight hours.
While adult predators and nest predators are the biggest obstacles to turkeys repopulating, the biggest human obstacle is that most turkey hunters don't do their part. They just kill their birds and hope there are more next year to kill. Take, take, take. And it's not just kill a few coyotes and coons here and there.... if you want to actually make a difference, it has to be an 'all out war' declared on coyotes and coons. When one shows up on camera, eliminate it immediately.
I guess what I'm saying is legalizing nighttime hunting of coyotes will help a tad...not because it's ineffective...but because most turkey hunters don't spend any time removing predators, so the net end result won't make a hill of beans for turkeys.
Now making everyone who wants to turkey hunt turn in 5 coyotes and 10 coons before they can get a turkey tag... holy cow, THAT would .ake a difference. (I'm not advocating that... there would be no turkey hunters that year.... BUT the turkeys would thrive!)