I've always liked the idea of putting latency requirements in to API specifications. Maybe that could help delimit what is and is not automatically inlined as the author proposes.
It's not about being picky. It's about communicating needs, and setting boundaries that are designed to satisfy those needs without overwhelming anybody's system to the point of saturation and degraded performance.
In the context of this blog post, what if the SLA was <100ms for an initial response, with some mandatory fields, but then any additional information which happens to be loaded within that 100ms automatically is included. With anything outside the 100ms is automatically sent in a followup message?