Please MS, increase development resources behind net and c# instead. It will benefit Java more than direct Java development - competition will give Java more motivation to grow.
C# with .Net should compete with Go and rust these days, fight for the mindshare of developers.
I think Mads Torgersen & co. are doing a wonderful job.
We've had a new version of C# with each new (recent at least) release of Visual Studio.
Did you have issues with the quality of new features? I'm really puzzled by your comment.
Besides apart from C# there's also CLR and Jit that could use more love. It is well known that jvm is a better vm than CLR. Most of the CLR speed comes from using references to value types but somewhat as an afterthought and without tools that C++ provides (readonly gives you muh less power that const reference).
Apart from Borrow Checker which is a recent invention, all programming languages features, as far as I am concern has been done previously in one way or another. There is only so many language features you can fit in on a languages like C# which is soon to be 20 years old. It is a sign of maturity. And C# in itself is already very modern compared to Java.
Most of the JVM performance improvement came from many Enterprise customers absolutely pushing the limit to a point where performance of JVM today would be unthinkable 10 - 20 years ago. It is the work a hundreds of millions if not billions over the past two decade. And it is not like Microsoft are not doing research on how to speed it up.
They are adding to the language, which is a mixed blessing, it is helping in some aspects, but also making the syntax even more complicated to a beginer. But the standard libraries are rather stale and would deserve a lot more love.