@loftie that's some really useful feedback, thank you for taking the time to write it down.
I love the Anno games however the first I played was 2070, so I'm probably going to pick this up so I can experience playing the game in an older setting, and if there is some good complexity and some changes (which it sounds like there is) to it then it will be good to play.
A lot of people point to 1404+expansion as being the best in the series, to me, 2070+expansion is very similar to 1404 with the obvious difference of setting, but it also adds an extra faction to a total of 3 (eco, tech, tycoons), there's the eco balace aspect which I thought was cool and there's underwater building. Hence why it's my favourite. It's been so long since I've played 1404 that I can't remember if there were any other differences or not. IMO, pretty much everyone has a sale on at the moment, grab 1404 Gold Edition as it's normally on sale at ~£3 - it's £3.12 on steam. Annoyingly GOGs sale is over, otherwise I'd have said grab it from there TBH. You can play in an older setting while waiting/watching to see how 1800 pans out.