The key issue is the change to get you 1 type of ore at a time vs it just giving you iron ore + the other types (randomly). The concern is that raising the non iron skills is much more difficult/slower now b/c the material count is less.
I am not sure that is 100% accurate but it might be given the changes and I think it feels a bit frustrating.
One thing already in effect recently is boosting overall skill level to 200 will provide a +10 on that roll for additional material types (level / 20) is the adjustment.
Possible additional changes
[x] tile type has a much bigger impact in the type of ore you get
[x] ore chances are more evenly balanced on a particular tile type
The key issue is the change to get you 1 type of ore at a time vs it just giving you iron ore + the other types (randomly). The concern is that raising the non iron skills is much more difficult/slower now b/c the material count is less.
I am not sure that is 100% accurate but it might be given the changes and I think it feels a bit frustrating.
One thing already in effect recently is boosting overall skill level to 200 will provide a +10 on that roll for additional material types (level / 20) is the adjustment.
Possible additional changes
Rarity order: until player become overweight