One thing that I'm really excited to start working on is aligning the Ember object model towards the new features coming in ES2016+. During the period of JavaScript-the-language stagnation, we had no choice but to add these features as runtime augmentation.

Now that the pace of evolution on TC39 and in the browsers is so much more vibrant, we can start pushing a lot of those features into the language itself.

That has two important side effects. One, it means huge swaths of code can be deleted from Ember. Two, and perhaps most importantly, it increases the chances people will already be familiar with those features once they try to pick up Ember, reducing the learning curve that much more.