Any particular reason you like Dart so much? I tried it briefly, and it felt like a watered-down mashup of Java and C# with somewhat worse performance.
Basically Google hired a bunch of PhD types to design something from the ground up that would run anywhere, compile to native, compile to JavaScript and soon to WASM. It’s fully object oriented but also has first class support for functions and everything that enables.
It has fully sound null safety, the tooling they have around it is also amazing for example code can rewrite itself to update to latest APIs and patterns just by running ‘dart fix’. But it’s a very boring and predictable language that’s easy to use and never really surprises me with quirks.
Right now it's less functional than Java, about as much as JavaScript (though in JS classes are less idiomatic so maybe it's a bit more functional in practice).
Considering what people are asking to add to the language (https://github.com/dart-lang/language/blob/master/working/05...), I wish people would start with a minimal functional language (Caml/SML without the modules, so functions, pattern matching and ADTs mostly) and then add things from there. It's a strong basis for a language, and people are going to ask for that stuff later anyways.
Also looks like they're going to include static meta-programming, so you can metaprogram at compile time rather than runtime like many languages [0]. With this, many language features can be implemented yourself rather than needing the language maintainers to do so, such as adding dataclasses or (React-like) hooks. And if the state of the art changes, the language won't need to be redesigned or more stuff bolted on, you can just swap out the old language feature (as a package) and swap in the new one.
(I wouldn't stretch to calling nim 'major' but I will say I've found it fascinating so far)