This proposal may sound unintuitive to programmers especially those with a long history with SFML. Let me address that I have an eye for markets, user ecosystems, and social engagement. It's in my interest to contribute to SFML in other ways than code namely image and growth.
The Issue
To put frankly,
"Simple Fast Multimedia Library" is a misnomer to developers and this is bad for SFML because users have misinterpreted expectations that lead to disappointment and abandonment altogether. Why does this matter? With the exposure Hospin's Minecraft, rise in modern C++ interest, Microsoft's VS video tutorial using SFML demonstration to name a few, we'll see an influx of new users wanting to try out SFML. With more active users in the community, we can gain more contribution, which means faster progress at lesser effort from the maintainers. Green thumbs for everybody.
It's Not Simple!
From my internet scouting and discord monitoring, I've noticed users come to SFML for interesting reasons:
GUIs, cross platform system software, games. When they find out SFML doesn't have a specific features like default fonts, controller libs, and batch rendering out of the box they're surprised.
What I think has happened is that they are misinterpreting "Simple" in SFML as being a one-does-all experience. Not realizing that SFML is actually a lightweight collection of common application development modules and therefore will require work and code for advanced features. This demoralizes them and they may quit, running off into the arms of SDL2.
It's important to note that as any industry grows (software in this case), the barrier of entry must get smaller. This is because people expect things to come easy. If the implication is to be "simple", the new waves of coders expects their hand to be held. We can prevent this by not promising simplicity. We tell the coder (potential customer if you will), what they can expect from SFML that can be met every time.
It's Super Fast!
Change the name to "Super Fast Multimedia Library" because SFML is super fast for dev time, prototypes, graphics instantiation, and cross platform building. With this name change, we remove the implication that things are simple for new devs and now they cannot be disappointed resulting in a better and positive experience for them, retaining them as a happy user and contributing to the community.
This name change also keeps the well-known brand "SFML". Some copywrite (text) will need to be changed and in the end we keep the strong SFML lettering we recognize, keep the logo, and only change the long-form name.
Sometimes something as effective as changing a slogan in business can have a huge effect on a product. This is no different.
In summary, change the name from "Simple Fast Multimedia Library" to "Super Fast Multimedia Library". Keep the brand name's iconic lettering "SFML" change only text on site and the docs over time. Form new user expectations that can be met with SFML as is, increase user experience, retain the user, more growth, more contributions, less work for maintainers.