LordofLinks,
disregard my post above. The Evil Men faction should have only Evil Men for Ringheroes as you suggested. I still feel we need 4 ringheroes though: Lord of Umbar, Suladan, King of Khand, and Rhun Emperor.
Fankil is too powerful and we don't know much about him, and evil already gets a bunch of super ringheroes: Sauron, Smaug, Saruman, Alatar (with Dorwinion eventually), etc.