> - Provides a familiar language with clean semantics and low ceremony
Smaltalk had it.
> - Provides the fastest dev iteration times (there's no compile step, just edit + run in Dart VM/Dartium)
Smaltalk had it.
> - Provides ~10x faster start-up times than JS with snapshots (Dart VM)
Smaltalk VMs, actually Self, were where the first usuable JIT compilers were developed.
> - Provides faster run-time performance, that's predictable and can take advantage of real integers and SIMD instructions (VM Only)
Self and StrongTalk were quite performant. SIMD was not available back then.
> - Provides a unified object model so all classes from all libraries are interoperable
Smaltalk had it.
> - Providing a rich, well-defined, consistent API, real collections, removing JS WATs, smoothing over browser quirks
Smaltalk had real collections.
> - Provides a unified and composable IO model: Futures and Streams (repeating events)
Smalltalk has streams.
> - Provides a new powerful way to develop client apps with Web UI (Polymer/WebComponents) offering unprecedented levels of encapsulation and reusability
Fare enough regarding WebUI, as the web did not exist back then. However Smaltalk is responsible for the MVC concept.
> - Provides optimal dev and deployment options, you never have to worry about choosing the smallest libs as tree-shaking ensures only code used is compiled and minified
VM pruning in Smaltalk environments for deployment.
> - Providing "full-stack" dev environment, e.g. same language on client and server
This is only true when using Dartium. Transpiling to JavaScript does not count.