Here is my wishlist. Note I'm not saying that there is no project out there that does exactly these things. But if such a project existed, I would be happy to promote it as the default GUI.
1. Non-native UI widgets. Highly controversial, I know, but I only use these different OSes because I have to, there is no value to me personally in using the native Coca-Cola widgets just because only these get subpixel polarization right. I don't care. What matters that it works on the common OSes and that it works well and consistently across the different OSes. And that it keeps working and survives a switch to yet another platform. 2. Written in Nim with an idiomatic API and DSLs. Of course. But! It should be compiled to a DLL so that my build times don't suffer. ;-) 3. It should offer a low level API too, powerful enough that custom widgets can be written easily. 4. Multi-threading ready with clear rules what can be done in a background thread and what not and how to communicate between threads. 5. It should support both the traditional "event based" mode and the even older "immediate mode" UI. And leave the choice to the final application which mode I need to work in. 6. Small footprint. You cannot compete with Electron based apps so don't even try. Instead make it run everywhere where a browser cannot be afforded. This can imply that it works well on embedded devices, but also and more importantly that it can be used in security critical applications. Nice to have: 7. If you only work with the very high level APIs and restrict yourself to certain widgets, make it so that it supports a textmode UI as well.
