As for the new regions, actually I would love to integrate new regions in my mod! Especially since having that much wilderness in populated areas doesn't make sense. But I haven't been able to acquire an appropriate startpos that doesn't have stability issues.
I'm a bit afraid of touching the startpos too much myself, because it is quite easy to destabilise the game, and I hate nothing more than a campaign that crashes after investing 50 turns. For me, the game being stable (as much as possible) is a very high priority!
And I'm not that good at startpos editing.