> That you're not writing in Java/Python/C#/Ruby should be pretty obvious.

I don't think it's obvious at all that the keyword "class" is going to be fundamentally different from whatever OO language you are coming from. Isn't this the single biggest reason why many developers have difficulty learning JavaScript?

> There will be near zero correlation between "class" and performance.

There already is performance differences between constructor functions and Object.create (in terms of initialization, that is).