What do you think about Fuji 18mm f1.4 for landscape photography?

There’s no right answer that applies to everybody, but for me the 18mm f/1.4 is the perfect lens for the scenario you describe. I used to have the 16mm f/1.4 and the 23mm (sometimes 1.4, sometimes f2, depending on whether I valued image quality vs. portability more at the time). But it really bothered me to have to make the decision between the two after a while (I am someone who thrives on constraints, and I don’t look for a specific shot or type of angle when I go out shooting but rather try to find shots that work with whatever lens I have with me).

So I rented the 18mm f/1.4 for a trip and fell in love with it. I find it much better than the 16 for group portraits (less distortion), and much better than the 23 for wide landscapes. Plus the newer construction with weather resistance and great build feels nice. (I also don’t like the manual clutch focus of the 16 and 23 1.4’s because I prefer to use back button focusing which is annoying with the clutch).

I was able to get rid of 2 lenses in my kit and replace with just 1, which for me is highly desirable (again, because of fewer choices and thriving on creative constraints). Note that I also use the 35mm, and these 2 primes (along with a telephoto zoom) are the most versatile combination with the fewest number of lenses for my tastes

So I’d say “yes”, the 18 can be a replacement for both the 14 and the 23 if you’re okay just getting the shot you can get and aren’t the kind of photographer who is looking to get a specific field of view that only a 14mm can provide.

If possible, I’d recommend renting the lens first and taking it out without the other 2 for a few days and see what you think.

Good luck!