Minecraft also has generally awful performance (although this is generally attributed to its being coded poorly, not java).

Yes, but Microsoft ported it to C++ as means to have a common code base across mobile devices, game consoles and desktop computers.

Yes. But I believe that Microsoft made an improved version written in C++ after the acquisition.

"improved" is a matter of opinion. The Java version has mod support and the editions are kept at feature parity.

I remember when they promised a modding api... Not even the C++ has resulted in one... The fact that Notch went with Java might have been a blessing in disguise because it made the reverse engineering process semi automated.