OK I did two test shots with the new Nikkor lens. It really looks like the new lens has considerably better coverage. The landscape photo is sharp from one side to the other, with no issues, and I never saw this with the old Optar. The exposure was too dark though, so it looks like I have to get used to the new lens having a faster shutter speed (both at low and high shutter speed).
I am guessing the old optar did great work for newspapers and such, but it is not so great if used as a view camera. You can get great shots if you keep the coverage in mind of course. However, I think I will be happier with the Nikkor 150mm.