If we're playing "What If" with High Lord expansions, this is what I'd like to see, starting with the realms that most need to expand their territories:
It's very small, and needs to grow. Europe is largely divvied up, so I think they should drop bridges elsewhere. What I'd really like to see is the CP declare war on the Living Land. They have plenty of reasons to do so. Edeinos are beasts, and God gave Man dominion over all the beasts of the earth, right? Plus, their religion is a blasphemy. A double blasphemy, actually, because not only do they worship a false god, they spurn technology, which is the only path to salvation. They've just gotta go.
Malraux could drop bridges into the population centers of Central/South America, the ones that have the largest Catholic denominations. Take over those areas and then try to fully convert them to Cyber-Catholicism before ever trying to move on Rome. Also, drop a bridge into Quebec, take that province, and then reclaim New England from the LL. New England should really be CP. I mean, c'mon, a region that has both MIT, and a history of burning witches? It's perfect! Since the buildings would all be destroyed by the LL axiom decay, and the population significantly thinned, you could even have a new, colonial type environment. Puritanical CP residents, cobbling villages together from raw timber, while also sporting cybernetic enhancements under their homespun clothes? It sounds awesome to me.
Aysle's gotta grow, too. When I ask myself what part of the world would fit in best with a bitterly cold, high fantasy setting, I think Russia. Traditional Russian folklore is filled with magic. Baba yaga, etc. We know Uthorion is the Gaunt Man's do-boy lackey. Have GM order Uthorion to attack Tharkold, as punishment for Kranod's mistakes. Uthorion would do it, even if it's not in his best interests to do so. The Gaunt Man is just that scary. So . . . Aysle expands into Russia, at Tharkold's expense, and we get some good medieval magic vs techno-demonic action going on.
Tharkold needs a win. Doubly so, if Aysle attacks and is taking territory from them. I say drop a bridge into Mexico City, and then expand north into southern/central California. Mexico City has a big population, and it would be a shame to let all that life-is-cheap gang violence there go to waste, swallowed up by the LL instead. As for California, it could become a post-apocalyptic entertainment capital. The demons could co-op the movie and television industries there, to make Hunger Games/Running Man-style "entertainment" for themselves.
Indonesia is an obvious expansion area. But if the Gaunt Man wanted to punish Tharkold for their mistakes, and ordered Aysle to attack them, he wouldn't just let the Tharkoldu escape to North America. So HE could drop a bridge there, too, and take back a little of what they'd planned to take for themselves. I can see a few Orrorshan zones in the Southwest. Arizona, Nevada, etc. Victorian-era technology is close enough to wild west tech (revolvers, stage coaches), that you could have a cool wild west/horror setting there. Native American magic; Sacellum "missionaries"; steely-eyed gunslingers, riding into town to handle a monster threat before riding off into a blood-red sunset . . . if the monster didn't get them first, of course. I think it'd be cool.
Kaah could keep the eastern seaboard and Midwest, and could pull off a healthy expansion into non-CP areas of South/Central America. He'd be doing well, but to soothe the sting of losing the west coast, he could drop a bridge into Australia. I like the idea of the Outback, but with dinosaurs and jungle-y areas added on. Rugged outdoorsman on walkabouts; Aboriginal tribes holding their own against the axiom shift, because they're still in touch with the old ways; the "Dream Time" as a cool new mystical element to explore.
The Nile Empire
I like the idea of a pulp Wild West area, if the Orrosh thing doesn't work out. Otherwise, just securing all of Africa for himself, and expanding into the middle east.
They've got a large, healthy population to chew on (pardon the pun) in Asia, with plenty of good expansion opportunities present, without even needing to drop new bridges elsewhere. They could opportunistically pick up new Core Earth areas on the sly, however, as the opportunity presents itself.
Those are my quick thoughts on the matter.