In general, that seems like greatest improvement that can be made, because they optimized language itself.
They made it efficient, but still readable, so you can just read or write the code without much/any Googling. I never really understood why simplicity was considered especially "junior-friendly", while actually more experienced people can benefit the most from it. It's much easier now to just visualize algorithms used in code, without introducing tricky notations. It's also much easier to just write your code, when you finally have syntax and stdlib that will cover majority of typical cases, instead of language, where you need to either reinvent the world or use over-engineered libraries to solve common problems.
Contrary to this mindset of simplicity over everything else, abstraction is the very bane of existence of the whole field. While there is indeed accidental complexity we should strive to avoid, there is essential complexity which can only be managed through proper abstractions.
So that over-engineered library that actually solves the problem is the only real productivity benefit we can achieve, since languages don’t beat each other in productivity to any significant degree (see Brooks).
So while one may not want to go into macro-magic with a semi-junior team, no abstraction will just as much kill a project because LOC will explode, it will have tremendous amounts of buggy copy-pasted/multiple times implemented code, etc. And the few empirical facts we know about programming is that bug count correlates linearly with LOC.
