Gwaja
King
Interesting stuff. I don't think that it's the right map for first tries on immortal. It's easy to expect several AIs in the range of 20 cities around Astronomy when sea levels are low.
After having played a dozen turn or so before heading to bed, I would say that it is gonna be highly unlikely that anyone will have 20 cities up.
This is archipelago map with archipelago land types, not snaky continents. If this was snaky continents with low sea level, then there will probably be a lot of land... but because this is pure archipelago, the cluster of land is not so big at all. The landmasses are a bit closer to each other, which means that more land is reachable before Optics.
Archipelago map with archipelago land type at medium sea level makes the land extremely tiny, and makes the island clusters even more separated. That means high chance of isolation, not to mention inability to expand as much until Optics.
Give this map a try... it is sort of an experimentation anyway. It is also probably going to be the last archipelago map for this series of games, but Ragnar just seemed like the right leader to play this map with.