So, a review of the changes:
Ads to use premium-features: These have been added everywhere, to an extent where it borders to harassment of the players. As a result, some windows now lead slower, farming village demanding in particular. Even as a premium user this is problematic. I play several worlds, but only use gold in one. If I have turned the confirmation window off, I can accidentally activate premium features in the other worlds through a single mis-click.
Island city icons: Looking on the map now looks very ugly and painful, and it's hard to focus what's on it due the the extremely shiny ads asking you to spam more people about joining the game. It makes it harder to get an overview when you look around, since it's hard for the eyes to differentiate cities and their different colours from the shining objects plastered around the islands.
Founding new cities: You can now only found in islands on the 1-2 islands that are in closest proximity of one of your own cities (apart from islands that do not have farming villages, where people should never found cities). This creates huge strategic problems within the game and is very limiting for gameplay. Even though this is a very misguided step by developers, I think they might have added it despite knowing it would harm the game, simply to encourage the use of the invite-function.
Support for mythical units: I tested, and I can confirm that you are now also unable to support cities without a god selected. No biggie, although a bit of a pain in the ***, I would say.
Battle points for support: My main fear is that this will make mass biremes, which is already very powerful, even more attractive, making the servers a little less exciting to play on. I have tested this, and the system distributes battle points between the defender and the supporters, likely giving the third of the battle points to the defender as minimum, and otherwise giving a percentage of battle points depending on the number of units (in population) that the supporter has in the city.
Trading window: An interface change has added zeros the the trading window. This is a useless addition, and makes trading worse since you now have to delete the zero if you're not going to use it and you have to be more careful where you click. Earlier, you could just click anywhere within a field to select it, but now you have to be careful of click the right place.
Once you have sent resources from a city, the numbers in the trade window will be reset. This greatly detracts from the usability of the trade window. Previously, whenever you needed to rebuild a light ship nuke or anything else, you could simply switch between your cities and click trade on all of them, but with the most recent change, you have to input the numbers for every trade, making it a much more tedious and time-consuming process. In much the same manner, it's no longer possible to add numbers to the trade window in advance (for instance, while you're waiting for a trade to complete) as whatever you write will automatically be reset if it exceeds your trade capacity.
Battle simulator: A nice addition allows you to quickly add the units for your current city. At the same time, it's no longer possible to add more than 9999 units the the simulator, so you cannot simulate a large stacked defense.
Selection in Reports-window: It's now easier to select several reports as you can click anywhere on them except the link to select. As a downside, you can no longer select any text in the Reports-window. Also, you easily end up accidentally selecting battle reports, and the new drag and drop function creates a weird graphic or dragging several reports across your screen.
Change of window overlap: The window overlapping now bugs out. So, if you have the building view or culture window open and switch to another city, the game will automatically switch to the city view if it's open, meaning that it takes a longer time to start buildings or city festivals in your different cities.
I have a feeling this game is heading towards its end. That's the only reason I can see for Inno to make such an aggressive move to get its users to pay more money.