I agree. If a photographer wants to slow down when making photographs, then slow down. (Like Joel Grimes said, try shooting everything on a tripod. That will slow things down!) If the goal instead is to play fast & loose, then do that. Don't use ease of use or features on a camera or any other tool as a reason for not working a certain way. I never used most of the features on the 645D, and now that the 645Z has even more features I'll probably use an even smaller % of what the camera can do. But I'll still take the benefits of the Z relevant to me and use them the way(s) I prefer to work.
I have shot the 645D in situations where more support for a fluid shooting style would have been helpful, like street work. It was a chore, and definitely wasn't playing to the strengths of the D. The Z is much better at that now. Some will say, why bother using a big medium format type system for that type of work? Why not shoot another system more dedicated to it? Lots of reasons. I like the aesthetic of the images that come out of my 645 system, I'm trying to streamline my digital workflow around getting images to look the way I want them, I'm trying to cut down my Gear Acquisition Syndrome (I keep looking at the Fuji X cameras, and keep finding a reason not to buy them
), and I don't want to travel with multiple systems if I can do with one, especially when that one is large & heavy as it is.
Still, a whole other area of my work is locked down, manual everything, tripod, slow & methodical. The Z will plug into that approach perfectly. There's not one reason to change anything about the way I do that work. Basically I see it as now getting a lot more range of shootability with the Z, in situations where conditions are more divergent. That's a good thing, and I'll definitely take it.