Well then, let discuss how Inca 3.0 improves Inca 2.0.
Mountains give 3f3g each one. I suppose you have to work them. How this compares to current +1 gold for every mountain in range without having to work them? It's a good tile to work early on, granting basically extra 3g to usually 2-3 city workers (3f is a farm on grass), while the other was just extra gold. But it happens that the same mountain can be shared by 2 cities, making that yield double good as it looks. Otoh, settling on a mountain frees this worker, and this is basically 3 extra gold. On the fun part, looking for mountains and placing workers seems more fun than just looking for mountains, but with automated workers placement there isn't much difference. Settling on a good mountain tile can be, though, as it is a more feasible action. I have to say that I like it more than current one, but the final outcome is the same: extra gold when settling near mountains.
Now, Terrace Farm. I like the concept of extra X if Y. It's like fresh water, you can build some things when there is fresh water. So, extra food and culture if there is at least an adjacent mountain solves some problems. It's like having long/short rivers, you don't care much as long as you can settle on the river. And this behaves better with the naughty sheep. Still, I dislike removing the bonus to adjacent farms. This wasn't the problem. It made TF feel like a farm. About TF yielding culture, I'm not sure. There are already 2 UI that yields culture (moai, chateau). The flat production bonus was well enough, so we don't regret not building mines.
To me, the weak point of all this is that everything is terrain focused. Miss mountains and Inca is the worst. Have some mountains and Inca is just a little better.