Meanwhile, the 450SR costs the same as the Ninja 500 (or 400 of old) while not being a better product, is really a tough sell.

To me, it's only a marginally better product in terms of specs, which is evened out by Kawasaki's brand value, history and reliability. That's just my opinion, we can agree to disagree.

Going to list down the current common known issues on the 800NK from my members group.
1) Coolant expansion tank crack
2) Signal switch failure
3) improper reading of fuel level
4) Factory muffler rear garnish/trim mounting broken off (maybe from bad welding on the bracket)
5) loosing bolts - needs to be periodically checked and tightened.
Other issues
1) weak hydraulic timing chain tensioner (also affecting all LC8C engines, including KTM)
2) Slow TFT. No Android auto, only car play. Screen mirroring for android is hopelessly unusable. Built in nav software is slow and unusable (cannot find names and addresses in search).
Some other issues could be bike specific due to various lapses in local build quality/QC or rare component failure.
Obviously the bike hasn't been in the market long enough for most riders to accumulate enough mileage to properly get a good indication of overall reliability. To date only 3 bikes have gone past 30k km.

However, so far no reported instance of cheese cam on the 800MT and the 800NK. So the engine and drivestrain seems ok for now.