In addition to the obligatory "mod parent insightful", I should add a comment on HL7: It didn't get that complex for the fun of it, but because medical systems are extremely difficult to systematise, and over time you end up having to add special cases and exceptions and exceptions to the exceptions and so on ad nauseum. As you say, Google couldn't even get the basic CCR implementation done ("hey, we can simplify things if we leave out this, and this, and this...") which ignored the fact that those things (well, at least some of them) were in there for a reason. HL7 has all of its "more than one instance of X" and "free-form anything" fields in various places for a reason...