[Edi]

MA R'lyeh already has a Traitor King hero, Shadul Ummuush, a mage with W5. A traitor Basalt King for EA R'lyeh would not be as thematic, but a Traitor Mage (a Mage of the Deep, precursor to the later Kings of the Deep), a powerful mage who fled the Basalt Kings and Queens because they would have slain him for being too ambitious.

Though it would make more sense that such a one would seek Oceania as a safe haven. Though you could probably have a Traitor Mage for EA R'lyeh and an Atlantian Mage-in-Exile for Oceania.

Jomon could probably benefit from one more really kick-*** samurai hero, somebody with an insane defense value and built-in fear and awe.

For Vanheim and Helheim, several possibilities are opened up by the Asmeg. Indies of a disabled poptype, descendants of the Aesir who survived the war with the Rimtursar. So some Asmeg heroes could well come of that.

For Ulm, EA & MA, a specialty smith hero. The idea is lifted more from Michael Scott Rohan's Winter of the World trilogy where the main character is a smith of extraordinary skill and power. Magics of F3A2E4W2S3 would be thematic for that one if you were to take the character as he was.

T'ien Ch'i could probably use an immortal general and possibly a hero who could shapechange into some kind of dragon.

The rest of my ideas I'm keeping to myself since I might use them myself somewhere (not necessarily Dom3) and thus they're not for public consumption.