At our company we came to the same conclusion. We have a DSL that is essentially a programmable schema to describe the shape of the data (more specifically a contract) you want to capture as well as how answers and decisions are derived from it. The only hard validation we have are types, eg. you can't put letters in a box that captures a number type. Other than types the rest is soft-validation which means that you can input anything, even if it is partial or not quite correct, and the system will do its best with what it has. In tandem, at any point in time you can ask the system to tell you what is missing and/or incorrect. All this then affects the lifecycle of the information, ie. you can't move past certain checkpoints in the workflow if the information is not in the required shape. In the context of a medical software imagine you can fill in just the things that will get you back meaningful answers to help you treat someone and you can deal with the rest after to make the case complete.
