In Sydney I saw a legacy-free setup for washing hands in a public bathroom. I was surprised at the simple and solution with high utility! It is only a board mounted in an angle with water taps above. For typical use (washing hands under a flow of water) this is as good as a traditional setup. From looking at it, the legacy-free setup seems much easier to clean. I have never used a washbasin in a public bathroom by filling it – and I have never seen this functionality used (typically you can not use it in the lagacy way as there is not plug)… nevertheless most setups have washbasin.
Back to computing – what does it tell us? Looking at the operating systems I use, the applications and devices I see a lot of washbasin! Functionality that is never used but makes maintenance pretty expensive is a part of most of them. Looking at architecture as well as user interfaces the above example can motive to look at non-standard solutions…