Over complicated business requirements are bullshit. But starting a product without researching first is a recipe for disaster, particularly if you are entering a crowded market.
Over complicated business requirements are bullshit.
What if the requirements are complicated?
Go ahead and develop an arbitrage system, a medical claims processing system, or a repetitive shop floor control system without "complicated enough" requirements and see how far you get.
My sense is that to someone outside the industry, such requirements would seem overly complicated.
A few years ago, I worked for a company that did patient management software (including billing). In the effort to get the product to market, they neglected documenting the requirements of the billing portion. Over time, because of the requirements of our each of customers were different (depending on what entity they billed, the rules for the billing were different), the application turned into a mess of stuff that was never well-documented (fortunately, I didn't work on the billing app). Had they done a bit business requirements gathering before building, they could have likely saved time and money by designing more flexible software.
It's also worth noting that this wasn't some big, lumbering corporation--it was a start-up.