Happy to hear you're enjoying the game!
In the period and setting of Anno 1800 there's a lot of room for all kinds of stories and places to explore. Unfortunately, we won't be able to cover them all and for now there are no plans to add additional regions to the game, which therefore also excludes places inspired by India, Thailand, China etc., but also Australia or the US.
That said, the team has had a lot of fun each time diving into the research for each region in the game, be it on a narrative or a visual level and for potential future projects, there are certainly some regions we would love to explore.