23mm 1.4 soft wide open?
I always thought my Fujifilm 23mm f/1.4 lens was pretty sharp wide open. Then I compared it to the Sigma 35 1.4 and found it a bit lacking in sharpness (see that test HERE).
So I decided to test it, here’s the results.
Test image

Whole image is like this
Varied apertures

100% crops, open in new tab to see 100% size
f/1.4. In real world use this isn’t too much of an issue as shooting wide open is more about using the shallow DOF to your advantage or just to get pure speed.
f/2.0 sharpens it some.
f/4-8 and it’s hit the peak of it’s sharpness.
f/11-16 diffraction kicks in little bit (increasing softness slightly) but it’s nothing to worry about.
Conclusion
My copy of the Fuji 23mm 1.4 is slightly soft at 1.4, sharpens up a bit at f/2 and is super-sharp from f/4 and onwards.
My recommendation would be to use f/2 for a good mix of sharpness and bokeh, unless you need the speed of f/1.4.