Mind Mapping is a no brainer for such situations. 1) I use XMind, which has floating topics. I quickly draft mentioned requirements as a floating topics and th

Mind Mapping is a no brainer for such situations. 1) I use XMind, which has floating topics. I quickly draft mentioned requirements as a floating topics and then break them down into sub-topics 2) After the requirement is clarified then it's a time for prioritisation and I use priority matrix for that. 3) Then you just unify everything under a central mind map topic and "connect the dots".