Hi. Here is a Suggestion to add Eraser tool:
It is a bit clunky for me to draw and erase with erase mode. For example, I draw with a hard round brush and erase with it, draw again and then switch to blend brush, use it and want to erase again. Blend brush don,t have erase mode, so I need to go back to hard round and if it is not set to erase mode I need switch it to erase mode. Same problem when you draw with a soft brush and want a hard eraser and etc. It's too hard always have in mind which brush was in erase mode and which don't.
More than, when I use another tool like an ellipse tool and want to erase part of drawn ellipse I need to get back brush tool and set it to erase mode.
The best solution is a separate erase tool which is not depending on the paintbrush tool. Everybody wins if we will have both options for erasing, it will be more friendly for persons who prefer industry standards.

I can't answer for what the exact development plans are going forward, but that topic was discussed at this year's Krita sprint:
https://dimula73.blogspot.com/2019/08/k ... n-and.html

For now there are two options:

You can use Tools > Scripts > Ten Brushes and put an eraser preset in one of the slots. Then under Settings > Configure Krita > Keyboard Shortcuts you can look for Ten Brushes and assign a custom shortcut to that particular slot. It doesn't change the tool you're currently using however, so you'd still need to switch to the Freehand Brush Tool.

You can also download and install the Direct Eraser plugin from the resources page: https://docs.krita.org/en/resources_pag ... on-plugins
Unzip it and put the pykrita and actions folders into your Krita resource folder, start Krita and activate the script under Settings > Configure Krita > Python Plugin Manager and assign a keyboard shortcut like it says in the description text and restart Krita again. Now when you press that shortcut it will switch you to the Freehand Brush Tool and activate eraser mode.

Side note - Blend brushes using the Color Smudge engine can also be used as erasers, but you have to activate the Color Rate property in their settings to see the effect.