I don't think that less lines of code automatically means code is more readable, but I'm a big fan of ES6' arrow functions. In this article Eric Elliott dives deep into them.
I also supect that your team would become significantly more productive if you learned to embrace and favor more of the concise syntax available in ES6. While it’s true that sometimes things are easier to understand if they’re made explicit, it’s also true that as a general rule, less code is better. If less code can accomplish the same thing and communicate more, without sacrificing any meaning, it’s objectively better.
Let's hope we'll soon have array functions in PHP too.