Under what circumstances would you NOT want a clean, sleek and minimalist website design?
Both questions have one target at the end and that is the Users. It highly depends on they type of users of your website and their willingness to change. Here are two good examples:
It is a highly content oriented website and the design is almost the same since a very long time. Why didn't they think of changing the design? If you look at the list of contributors and even everyday users, they are all aged people who are too used to the features of the website that if you ask them if they would like to use a new minimalist Wikipedia - they will say NO, mainly because they are not ready to change.
If you remember the basic web version of GMail you will understand how far it has come in terms of keeping it clean and minimalist. But, even today they had to preserve all design options such as: Show me the basic GMail, classic view etc. because they don't want to lose any type of users.
Google launched Inbox back in 2014 but even today it has been placed as a option in GMail for users to try and continue using it or switch back to the older version. What it means is GMail is changing but they also keeping the not ready to change people active with their preferred option available.
In 2010 the social bookmarking site Digg.com launched a website
redesign that led to a 26% loss in web traffic. The site updates
alienated loyal users who found the redesign so off-putting that many
left and never returned.
Don’t Do A Redesign! Learn Why Evolution Beats Revolution
Under what circumstances would you want a clean, sleek and minimalist design?
A) Twitter / WhatsApp / Spotify:
The users of these websites and apps are mostly tech savvy and every new upgrade or design change will give them the WOW feeling (considering the design is reducing clutter).
10 tell-tale signs that your website may need a redesign