Ian, I thought this image might be helpful for this discussion. Maybe not, we'll see.
I compared the profile of both my wakui 240 and kochi 240 gyuto to my itonimmin 180 nakiri.
As you can see, the wakui is, indeed, pretty much a nakiri with a tip and a little less height, while the kochi (image on the right) has a considerably different profile. I didn't shoot my ginga, but it's even more "different" from the nakiri than the kochi is.
I've never really been attracted to a 180 nakiri as an all purpose knife, mine makes it's living on all kinds of cabbage and chiffonading collard greens for caldo verde. (it may come as no surprise that I made cole slaw for dinner last night).
I used to have a little 165 mac nakiri that I thought was a much more generally useful knife, but not actually so great at cabbage and greens in general.
I decided on the itonimmin rather than a watanabe because it was half the price and I didn't think a nakiri was going to be useful enough to justify spending twice as much on one. I was right, but, who knows, self fulfilling prophecy?
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