Dpreview listed five things Nikon has to improve on the Z7:
It’s AF where we’ve seen the most serious issues with performance. Unexpectedly, the native Z lenses we’ve tried appear to focus more slowly and less predictably than adapted F-mount lenses too (though to their credit they are silent to focus in video).
In most other respects the Z7 is an impressive camera. We’re optimistic that where we have concerns, Nikon can address some of them via firmware, and others via new dedicated flash accessories. Our other concerns? Perhaps we’ll just have to wait for a Z8.