A tech that reveals iron before iron working would be very nice.
Yeah, maybe spotting iron in Bronze Working but waiting til Iron Working hasn't been an issue for me... makes sense you don't notice it prior to being able to use it as it is merely part of the terrain until it becomes important (gems, copper, gold, silver are bit shinier and tend to attract attention so I never had issues with seeing most bonus/luxury resources prior to being able to use them).
Horses, on the other hand, have always annoyed me. I feel they should be visible from the start of the game. If I can see herds of cattle (even worse, elephants/foxes/swine or whales) before I can tech to make use of them I should see the herds of horses. The one issue here is the bonus they give (+1
![Production :c5production: :c5production:](/images/smilies/civ5/production.png)
) which wouldn't make sense before Animal Husbandry when you employ animals for labor (+1
![Food :c5food: :c5food:](/images/smilies/civ5/food.png)
from cattle/sheep does as prior to making use of the animals for labor you can still eat them and the bonus gold from the luxuries also follows suit, you just get more when you can hunt them effectively). Maybe giving them
![Food :c5food: :c5food:](/images/smilies/civ5/food.png)
bonus prior to teching Animal Husbandry and remove it and replace it with
![Production :c5production: :c5production:](/images/smilies/civ5/production.png)
then; however, I've yet to be able to give bonuses to resources via tech (only improvements which won't affect the resource when a city settles on it directly).
I suppose I could link it to stables (since you're considered to have the resource improved by settling on it) but it'd still mean you'd effectively be eating the horses before the city has a stable...