Lean requirements management or why RS is not required any more

Throughout my career, I have heard that the result will be unpredictable without a requirements specification. That the result of the analyst's work is well-written documents. 

But over my 15 years of practice, I have become increasingly convinced that in 90% of cases, large detailed documents with functional requirements not only incur huge costs to the project but also often harm the project/business. 

That is why for many years, I have been trying to get across the idea that the main task of an analyst is to think with his head and convey the real pain of the customer to the development team. And none of the normal developers would want to read the requirements specification for 200+ pages. 

As part of the presentation, I will talk about the practices of lean requirements management that I use when both the wolves are fed (the business is satisfied with the result) and the sheep are safe (the team is alive and safe, eagles).