Apart from some of the opinionated "you should be doing it this way" stuff, if your not using a lot of this your probably providing a sub optimal experience for

Apart from some of the opinionated "you should be doing it this way" stuff, if your not using a lot of this your probably providing a sub optimal experience for someone somewhere using an old browser. I guess it depends how much you care about backwards compatibility over just building for the latest and greatest, each project will be at a different point on the scale of what they need to support.