Is that likely to have a significant impact on the way we write Javascript today?
No. JavaScript is (now) important enough that no one person has that much influence over it.
This is, somewhat surprisingly, not true, especially if you're just considering the language proper. There are about 15 people who are regular members of the committee, and some of them end up having a big influence.
Brendan is a prime example; his language design taste and leadership matter a lot. There are certainly other examples. Dave Herman, also at Mozilla, has been the lead on a whole host of things, from extending iterators and generators to the design of the new module system, which I worked on as well. Tom Van Cutsem and Mark Miller created the Proxy system.
Outside of pure JS, the designers of WebGL/Typed Arrays and WebWorkers have both had big impacts.
Ultimately, even on a committee, individual people can make a big impact.