Startup Idea: Development of Improved Requirements Analysis Extension for Excel and Visio

Startup idea to solve inefficiencies with requirement allocation models in the aerospace industry. This involves developing an extension or add-on for Microsoft Excel/Visio that would aid requirements analysis engineers in better tracking and visualizing requirements at various levels.

I am a requirements analysis engineer in the aerospace industry in the Southern California South Bay region. On a day to day basis I struggle with using the IBM Rational DOORS package for requirements analysis and management for projects. It's the industry standard just because it has been around for a while, but to be honest the software is terrible in terms of a usability perspective.

What I desire is a small database expansion-pack type of addition to the Microsoft Excel/Visio suite that would show how requirements "fan out" between different allocations. Something like: requirements at the highest level requirements at lower levels requirements at even lower levels ...etc

Excel would keep track of the requirements and artifacts themselves, where as Visio would show how the requirement "tree" between different tiers would look like.