I already own a CB500X, which is similarly heavier and has more horsepower. It has been a decent moderate ADV bike for me, as was the CB500F I had before it, and I'll keep it for now. But I'm forever hoping for a lighter bike because it doesn't need as much horsepower for similar performance. I had a Ninja 250 a few years ago and just took off the fairings, made a simple stone guard out of stuff from Home Depot, put tubes in the tires so I could air them down, and rode with my buddies at an offroad vehicle park. I took that Ninjette moto-camping and rode it to Mexico. Given that experience, I'm convinced that a mildly ADV-ized Z400 could be great fun. Nobody would expect to ride it across Siberia without any problems, but for the easy adventures that a lot of us do, I think it might fit the bill nicely!