Non-national heroes

[Treebeard]

The game is pratically gold now, so this idea may only enter through a patch, if at all, but I think it's a good one.

I was thinking about heroes that would appear only if you have possession of a type of province, like the druid one, allowing the 'Elder Druid' (nature 3/priest 3) hero to appear through an event.

I can think right now about Amazon Queens, too, as extra heroes.

Perhaps it would be better to make them harder to come by.

Thoughts, guys?