Yeah, this is one of the things on my list. It's certainly senseless for Priest Lords to be unable to see the troops in their region, whether or not the restriction still makes sense generally.
I would add that priests being unable to see troops is ridiculous on a few other levels:
Only nobles with troops can arrest priests. Yet priests have no idea if any of the nobles in the region has troops.
Militia can resist some priest activity. Yet priests have no idea if there is any in the region.
Mobile troops can resist some priest activity. Yet priests have no idea if there are any in the region.
It's fine that they aren't meant to act as scouts, but they can be arrested by realms at war anyways.
Priests have no way of assessing the risk of any of the activities they do.