I get where you're coming from but the problems are orthogonal.

Let's say that each research study spends 10% of its time on recruitment and another 5-10% of its time on compliance. (Real numbers can be much higher).

Open medical data would reduce both these efforts, so every study, regardless of quality now goes more quickly and/or is less expensive. This is the primary benefit.

Now you're pointing out that extremely open data can lead to rapid and perhaps erroneous analysis. This is true, but it would also lead to rapid and accurate analysis. My point is that everything speeds up and compliance regulations around data handling are far less impactful on study quality than are protocols around experiment design.