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I have been on many many projects.  Sure some don't require elaborate requirements depending upon the size, complexity, criticality, scope, costs, resources, experience/wisdom/knowledge etc...  but many do - at least a baseline of SMART requirements which evolve. The best projects I have been on have been iterative, incremental and iterative in approach involving key SMEs/stakeholders producing prototypes and proof of concepts with a SMART baseline of requirements which evolve with time to manage scope, costs, resources, schedule, quality, risks...  

I have been on many many projects.  Sure some don't require elaborate requirements depending upon the size, complexity, criticality, scope, costs, resources, experience/wisdom/knowledge etc...  but many do - at least a baseline of SMART requirements which evolve. The best projects I have been on have been iterative, incremental and iterative in approach involving key SMEs/stakeholders producing prototypes and proof of concepts with a SMART baseline of requirements which evolve with time to manage scope, costs, resources, schedule, quality, risks...  

Without requirements where will you start?  Requirements allow you to prioritize, categorize, trace, realize, measure/monitor/correct accordingly and continuously and risk assess.  I've been on projects where scope was all over the place, so were costs and resources were heading in every direction.  Requirements were no place to be found and the project. A baseline of requirements which evolve provides direction.   

Without requirements where will you start?  Requirements allow you to prioritize, categorize, trace, realize, measure/monitor/correct accordingly and continuously and risk assess.  I've been on projects where scope was all over the place, so were costs and resources were heading in every direction.  Requirements were no place to be found and the project. A baseline of requirements which evolve provides direction.   

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