Since ES6/2015 the changes have been pretty minimal, so I disagree with your assertion. Since 2015 I find that async functions is probably the most alien addition... and the handful of others that are significant are mostly ignored or very natural extensions.

The shift from callbacks to promises is kind of alien, but frankly that was started well before 2015 even. The .babelrc I use for node projects is pretty simple as well, here's one I use for an AWS Lambda build...

    {
      "presets": [
        [
          "env",
          { "loose": true, "targets": { "node": "6.10.3" } }
        ]
      ],
      "plugins": [
        "syntax-dynamic-import",
        "syntax-object-rest-spread",
        "syntax-async-generators",
        "transform-class-properties",
        "transform-decorators-legacy",
        "transform-object-rest-spread",
        "transform-async-to-generator"
      ]
    }

So that's literally 3 things that aren't in spec yet, and a couple that work around the runtime not having them. Most of what's going in is already in, or relatively well established and on the way.

Now, you do have to include a lot more if you want IE11 support, but hey, that's a different thing. I'm not sure what exactly you're having a trouble wrapping your head around.