If I'm understanding it correctly, fish food actually got a buff: base is 2F (1 for fish, 1 for sea) and +3 for improvements (1 from boats, 2 from Lighthouse) = 5F, compared to 4F in previous. Gold nerfed by 1 though - a fair trade I think.
Hmm I missed the change that fishing boats provide food instead of gold (forgot how weak they are in vanilla). Nevertheless, all the boat adds is +1, or does the lighthouse bonus for fish only work when its improved? That for sacrificing the boat, a lot worse of a deal than improving something with a worker.
As for culture, my very personal definition is that there are two different kinds of things that are cultural: things people talk about in a way that is independent of the talked-about thing, and things that a lot of people come together to do, with no other purpose than doing the aforementioned things.
So if you wage war to conquer land, it's not cultural, but if you write a book about it discussing strategy and tactics (like the Romans did), it is. If you play an instrument for your own enjoyment, it's not cultural, but if you discuss the best tunes with a friend, or play for a hundred other people, it is.
The level of refinement is not a major part of defining something as cultural, but to reach a high level at something, you have to talk about it and discuss with others, so highly refined things are often cultural. They are not cultural if all you talk about is "how can I make this work in the best way", but they are if you start talking about philosophies or reasons why things work, in order to improve them.
In fact, some of the things we now perceive as highly cultural were viewn as mundane or mechanical in prior centuries - painting, for example. But since art in general is very emotional, it compels us to discuss it, or gather to look at it, and it becomes cultural over time.
The Aztecs are a bit of a grey zone in my definition but I would say their wars were cultural, or at least led to cultural pursuits at religious ceremonies where they sacrificed their captives, and some wars were fought primarily to capture sacrifices, so they fulfill the second definition.