> On the other hand, if fish doesn't work to your liking out of the box, and for many people it does not, there's no "messing with it" that's possible. You are forced to give up and use something else. Your reason to choose fish is only a good reason if you already agree with every minute choice the developers made and refuse to let you adjust.

Which part of fish makes this impossible? You can tweak the startup, the completions, the key bindings, the prompt, and so on.