A standard communitu map is 79x53 tiles. Land percent is 40%. That's 1674 land tiles. There are roughly 210 tiles for each player plus 2 city states. City states first two rings are avoided, that's 34 tiles less. So each player has around 175 tiles to toy with. If we want 8 horses per player, with stacks varying from 3 to 4, that's 2.3 stacks per player, 18 in a standard map. This means setting the frequency for horses at 76 (1 horse stack every 76 eligible tiles). But not every tile is allowed to have horses, they are around one third of the workable land tiles. So the frequency should be 25 for all the lands that can have horses together.
Currently the frequency is 20 for grassland, 32 for plains, 40 for flooding (half sized), 70 for tundra (half sized). With a minimum distance of 1 or 2 (choosing randomly). When there are not enough major stacks created (they are not), several minor stacks are created until 64 horses can be counted in the map.
The same goes for iron, major iron deposits have 3 to 4 iron units, so each player needs 2.3 major iron stacks. That's a frequency of 76, but since iron can happen in pretty much every terrain, it will be enough with a frequency of 75 for all the lands that can have iron together.
Currently the values for iron are 75 for hills, 100 for grass or plains without features, 40 for desert without oasis, and 90 for flat tundra.
Then there's a 90% chance to choose iron for the following distribution: 45 for forest hills, 50 for forest flat, 60 for forest tundra.
Then there's a 40% chance to choose iron for the following distribution: 7 for snow. (Consider how rare snow is, with this frequency you see at most 2 stacks in your snowy area for the whole map).
Iron needs fixing, in my opinion. If I keep iron in snow and barren deserts to spicy the games, then the other terrains should get frequencies around 90 (1 iron stack every 90 tiles of that type of terrain). Especially iron on forest, it happens too often.
