You forgot to mention that the Z400 also has no crash protection, either OEM or aftermarket; no provision for luggage (no, backpacks aren't luggage); no weather protection ( I guess the Z400 rider could try to use an umbrella - good luck with that); no available wire wheels for off road riding; no OEM built in electrical accessory circuits. The Z400 also has no dual floating disc, radially mounted caliper front brakes; the Z400
does have plain old front forks, while the RX4 has adjustable inverted front forks. The Z400 has a small 3.7 gallon gas tank, the RX4 has a 5.3 gallon tank. The Z400 comes with a 12 month limited warranty, while the RX4 has a 24 month unlimited warranty.
I guess it's true what they say - "You get what you pay for." For the added features that the RX4 brings to the table, I'll gladly pay the extra $600 every time. As to your opinion of it's looks, well, like the saying goes - "Opinions are like a******s, everyone has one." You're certainly entitled to yours, even though it's wrong.
(Don't feel bad, it happens to the best of us!) Having said all that, the Z400 is a nice scoot; and if Kawasaki ever sees fit to put their 400 cc engine in an ADV chassis, I'll certainly give it a look. But right now, comparing the Z400 to the RX4 is like comparing a claw hammer to a sledge hammer - they'll both drive a nail, but one will do a hell of a lot more in addition than the other.