That’s a feature for me 
I hated it when I tried to paint anything in Artrage 5 and I was getting something weird and circular instead of the brush shape that I was using. Obviously when I paint, I want my eraser to be just like my paint brush, just removing paint instead of adding it. And recently Photoshop added eraser mode similar to what Krita has
But for those who struggle with the different concept or are working with lineart (which can show some of the advantages of a separate eraser tool or at least a way to disable some brush dynamics like Size) there is a plugin called Ten Brushes which allows you to switch to some specific brush when you wish to do it using a shortcut. After some customization, it should fit the purpose. It’s available in Krita by default. There is also a dedicated Eraser plugin: Krita Direct Eraser Plugin
There is also ‘/’ shortcut that switches to the last used preset, and Brush History docker, so while it might look less convenient, after an initial set up it should all work quite well.
That should be easy to do, the only issue is, as far as I remember, that no one said what math this height mode uses. And of course it still needs someone to implement it…