Beyond that though. Not just V2.0 of the EMR systems, but V2.0 of how we think about medical data.
Yes, your personal data is your personal data AND each individual represents data points that are relevant research/epidemiological data for their age/sex/smoking class/alcohol class/ etc ad infinitum. I think the bigger part of the revolution is going to be in the legal aspects of how that population level data is accessed/who is allowed to access it.
With the example you listed about 'sadness' and 'depression' I think a sufficiently intelligent program like Watson would be able to parse all of that into meaningful 'buckets' like that researcher in Ohio, but at lightning speed and can report results in such a way that individual patients are protected.
As part of one of my current protocols, when a patient gets admitted to the hospital, I have to generate a 'shadow chart' that details each days testing, how much IV fluid and what kind the patient gets, how much and what exactly they eat, med lists, etc. I'm basically making an anonymized copy of the main medical record for their admission. Watson could do the exact same thing en-masse if we gave it the permissions and guidance to do so. Then, with (God I hate using this word) standardized, anonymous description of clinical courses of diseases, we could then turn our super-doc program loose on those reports to extract statistically meaningful data both about disease and about the efficacy of contemporary treatments.
I agree that I don't see it happening with what we have now. But I think that what we have now unsustainable. Research institutions are scrambling to find a model that really WORKS and they are trying to maintain the facade that they know what they are doing, which, from my observations, they don't. The high-level decision making positions are filled with geriatrics who at best don't understand the potential value that ML can bring, and at worst, are openly hostile to automation and technological advancement. There are old docs who maintain the mental and philosophical flexibility to be open to radical, systemic change, but it's not common.