There are a few elements to this request. We're currently looking into making some additional improvements in the area of packaging & configurations maintenance.
With the release of Custom Objects we have made some enhancements to Application packaging, so that you can download an XML file of an application.
Once you have created an App from a selection (or all) of your configurations and published the App, you can now "Download XML" version from its Details page.
By publishing you're not making it publicly available, just making the Application portable, if you do want to move it between organizations.
Often, people want to compare between 2 versions of an app or 2 environments, so the full internal details of rules is very important, not just the names/ last updated. With that Excel format won't be a great format as the configurations can contain multiple steps with complex formulas and therefore are quite large. XML is a structured format and there are many tools available, both on the web, or as developer tools, which can do DIFF review.
There's no rule of thumb about # people asking for a feature before we start working on it. We have many (hundreds) of fantastic feature requests from customers as well as those from our Customer Success, Professional Services and Sales Engineering teams and we constantly evaluate those in the context of more strategic roadmap features that can add value to lots of other users/ feasibility/ level of effort and more. We also deeply review feature requests when we build new or re-do functionality.