[mst]

Well, you won't impress anyone with a rather dismal Nikkor 24-120mm ;-) even although it may have an effective f/4.

Depends on what one needs to see in an image to be impressed. If it is optical perfection, from high sharpness to low distortion, CAs and vignetting to field curvature to smooth bokeh, then I can't name a single standard zoom that is impressive.

Fact is, though: even a dismal Nikkor 24-120 VR offers creative choices that are simply not available to future owners of the 12-45 Pro. Results that are potentially impressive because of the relatively shallow DOF in combination with the chosen topic, composition and background are possible with the Nikkor, but not the Oly.

For me, having that choice if required is important. For others it may not.