If you don't like the C#-ness of Typescript, try using Facebook's flow. Typing isn't a magic bullet, typescript isn't even type safe, but it sure makes development easier and your apps more stable.
That right there is the whole essence of typed programming :)
Again, it all comes down to cost-benefit. A new, modern 21st century language should be designed with the above in mind. The type system should make the resulting apps more stable, stay out of the way of coders reading code and writing new code, yet enable powerful tooling that doesn't need a heavyweight background process running a O(n^4) algorithm to collate meta-level information to enable all the IDE features. (Ideally, the tooling should be able to parse everything it needs to parse at some small multiple of the time it takes to read the source files off the drive.)
Again, it's all about cost-benefit! "Elegance" or popularity with tech hipsters be damned, what's the cost, and what does it get you? (The nickel-and-dime costs of waiting around for lugubrious and unresponsive tools not only add up, they operate with some huge multiplier effect.)
But sometimes I don't care exactly what sort of number is used. This is where many type systems go overboard, by forcing me pick a 64 bit unsigned integer or whatever.
I assume the original poster is talking about how few types you actually need to write in Flow because of how good the inference is.
One big thing is TypeScript classes are entirely different than standard JS classes. I guess you don't have to use them but it adds Abstract classes, interfaces and access control (eg private, protected vars).