To improve participation, some financial incentives could help. For example: 1) Cash prizes for the top 3 stairwalkers as registered on the website. 2) 10 pence off your Tube fare if you took the staircase exit in/out of the Tube station.
A possible way to extend on your concept (or maybe you already had this in mind).
If the app timestamped your every update, your wellness history can be graphed against time to provide some feedback. A bit like a stockmarket chart, which tells you whether your "family" parameter has been going slowly downhill for the last 2 years, or if your "work" parameter goes downhill on particular months.
You can use that feedback to warn yourself of an likely downward trend or make you reflect on why certain months are good/bad for you.
I like the output from this app, but I wonder who and how the inputs come about?
The app/visualisation must be accurate and very much up-to-date in order for it to be effective. As soon as people notice that it does not reflect reality, they will start to ignore it. In large dynamic companies where projects and roles and changing frequently, it's very difficult to rely on individuals to "push" data to update the app. On the other hand, relying on higher management levels to update the app may create a biased view.
It would be quite neat if a computer "pulled" and analysed the big data that is going through the computer networks, and updated the app/visualisation in real time.