What a beautiful, elegant dress, and what a stylish woman!
I can really see you in this dress, Deborah -- or something similar. It fits right into your aesthetic and would be useful.
Wearing the same dress in different colours would be a twist on your approach of wearing different (but aesthetically consistent) items in (mostly) one colour (in your case, black). It is a different way of embodying drama and simplicity. And it has the advantage of allowing one to play with flattering colours, which for some people can give a greater feeling of variety than switching up the silhouette.
I also see the appeal of this kind of dressing. It combines the "uniform" and the "signature item" all in one. Talk about making life simple!
I love the way it sends a very clear message about who she is and how she wants to appear.
A huge part of me is attracted by this wardrobe strategy. Not necessarily "one dress" -- but a part of me would love to head in the direction of a uniform. The trouble is, I can't settle on what that uniform might be. Maybe because my roles in life are so varied? I do think that is part of my dilemma. My varied climate also plays a role.
This dress looks exceptionally versatile. And yet I wouldn't feel comfortable in it in many of the situations I encounter. The pub literary reading, the school run, the meeting with a student (or even the university classroom -- it would come across as ostentatious in that setting). It would also feel like "too much" for my work-at-home days. It obviously wouldn't work for fitness or gardening or snow shovelling or skating with my daughter or visiting my friend who lives on a farm; perhaps it's not fair to expect any uniform to do that. But those are a big part of my life.
I think this may be why a strictly limited colour palette (vs. a strictly limited silhouette) is the way most people go when they choose a uniform. At least then you can still choose the level of formality you need. And the clothes can be functional for what you are doing.