My first rant is that I'm finding arrow functions unreadable.

Depends. If used instead of function (){} then arrow is ok. If used instead of function FuncName (){} then heck no.

Welcome to devrant, i advise you dont try functional languages

I Love it, because this is what i think it shuld be. You get use to the syntax quite fast... However i like:
(data) => {}
more than
data => {}

The same with let. Finally variabler limited to code blocks. And No wierd var always declared att the start of the Scope... Its declared where i declare it. :-)