Do we want to allow for users to stage-x plugins with this preset as well?
Or should this only cover for everything under latest?

Since browsers don't implement stage-x features anyway (otherwise they'd be stage-4), it would be only supported by browsers through a flag...

Maybe we should just leave it alone and users will just specify stage-x presets individually?

{
  "presets": [
    ["env", {
      "targets": {
        "chrome": 52
      }
    }],
    "stage-2"
  ]
}

Actually now that I think about that seems fine?