The discussion will be endless until we define the objectives, milestones and document the same. It brings discipline in project course and output is a product which can be taken to any height, think of Google Drive, Facebook, WhatsApp, Twitter, Instagram, Google Apps for Work etc... if they would not have documented their ideas, would they be able to have such a huge products as neither all ideas pop-up at ones nor executed so they document their ideas (generally they call it product back-log).
However we also feel too much extensive documentation also hinder the productivity as no one want to read a document of 10001 pages, therefore we believe in blueprint of the project, just like you would create with help of an architecture before starting the building.
We typically have following documents template created in this phase which allow anyone to grasp and a quick understanding of project (our project document templates are precise and subtle) :
1) Project Description: This document is generally requested from client in his words which help us to understand base of his requirements and from there we dance with him in rain of questions.
2) MoM (Minutes of Meetings): This document will enclose a chronological list of discussion session we will have with client including both before project and after project.
3) Story of the project: This document will give a walkthrough to anyone through the complete project story as per the user type along with assumptions and exclusions.
4) ETA (Estimation Time of Arrival): This will be an excel sheet derived from the story document along with efforts estimation for each feature, all features divided into delivery milestones/dates and corresponding payment milestone along with all necessary details and terms for the project. This single document will be able to address many questions related to project and that too very quickly.
5) Info Document: This document will have all the access details related to project like Hosting Access details etc...
6) Wireframes (Optional): In this we create skeleton of all major pages required in project, these are useful for complex project and also help client to save cost and time if client is not very sure what he want.
7) Change Requests: This document allows us to lock features which are assigned us additionally from the initially agreed features, scope and project time/cost.
8) Bug List: All the issues rose by client or our tester is locked in this sheet in chronological order along with status of re-test and system testing.