It pains me to watch Rust slowly repeat all the mistakes of C++, piling on new syntax and features every year with reckless abandon. http://smallcultfollowing.com/babysteps/blog/2018/08/13/never-patterns-exhaustive-matching-and-uninhabited-types-oh-my/ …
The problem with kitchen-sink languages is that you can never master them. Not just because they're big, but because they're not stable -- they have to change over time in order to keep everyone happy. Only a small language can be truly finished -- and truly mastered.