I don't think datamine spells and effects are bad, per say, they're just troublesome when easily accessible in large quantities. These should be given as rewards or quest goals:

"For your valour in defending the temple, the seer of the war god offers to divine an answer on an upcoming conflict."
"within the dragon's hoard you find a magnifying glass wrapped in fine silks, with faint divination magic radiating from the tool."
"After cleansing the lake, the water begins swirling as the form of a giant serpent made of torrential flows breaks the surface and approaches. the water weird thanks you, and should you ever be in need of help with healing, will guide you true"

Going to fight an orc warband? the seer tells you where and when is the best time to engage them, as they're trudging through fresh mud and slowed to a crawl. The faint magic in the glass fully identifies the unknown rain-summoning properties of the magic chalice you found before the lens cracks and breaks. ally died fighting that orc hoard? the water weird tells you of a dungeon where you can find the diamonds needed to resurrect your friend.

Heck the ritual for something like identify could very well be widely known but the reagent needed could be rare in itself or a highly guarded material, or the ritual only capable of being cast under certain conditions, like after casting your gift(ie: material component) to them under a full moon with clear sky, the various gods (or their proxies) will attend and see the ritual and weigh in with their specialties and gift you the answer. is it overcast or raining on the night of a full moon? no identify for you.

This is how datamining spells and effects should be used IMO: Information should come with a price.

The price just shouldn't be an 8-hour sleep and the time it takes to have a light breakfast.