I think the spec sheet gives you some base information, but I agree that it certainly doesn't tell the whole story. Having reviewers on site is really the only way to showcase those intangibles (i.e. ergonomics and user experience) though, which is how we get into this impartiality mess. If camera companies want reviewers to try out their cameras in an environment that showcases the camera's capabilities, the reviewers are likely to get flown out to a test location and thus impartiality will always be questioned. The same thing (and concerns) happened when Sony flew reviewers out to New York to test the a9. I don't think I have seen one review of the EOS R that forgot to mention the key shortcomings, so I'm inclined to say the reviewers are not giving the camera a break because they went to Hawaii.
At the end of the day every camera model offers a package or combination of those desired features at a price point their parent companies feel will be compelling. Canon has been frequently ridiculed for releasing bodies which are missing one feature or another, but they do almost always have a separate feature which is unique to their system and presents a different value proposition. This characteristic that Canon is so frequently ridiculed for may actually be its greatest strength - omitting some features in favour of adding features which are unique to the brand help to distinguish their company from others while keeping price points comparable. Obviously if Canon included all the features people are missing in reviews, the camera's price point would likely have to increase, or they'd have to remove some features unique to the camera. For instance, the R's features which seem to be really driving the ire of reviewers are single card slots, no FF 4k, no 120 fps at 1080p, slow burst mode, eye-af single shooting only, no rapid silent shutter. On the other hand, the R comes with several features which are unique and can only be found on their system (and in some cases maybe in one more camera) such as: flip/rotate screen on full frame mirrorless, control ring on lenses, sensor protection by shutter while camera is off, drop in filters on adapter, focus at f/11 (2x tele on many more lenses with af possible), focus at -6 ev, and arguably the most exciting launch lens lineup (subjective to be fair). It seems that Canon believes that the unique features list is going to drive more sales than the missing feature list will lose. I don't know if they're right, but I would say if given the option to choose between having all the features missing from the R or having all the unique features from the R, I would probably chose the R's unique features. To each their own though!