Simple idea. Can we use Tools in Pop-up Palette, not only Brushes?
And for heaven's sake, where is a feature request button in Krita’s issue tracker?
There are only functionality for bugs.

Feature requests are bug reports with the status "wish". Note that it's better to discuss feature requests first with the artist community on krita-artists.org. And we're overloaded with wishes already: there are currently 440 open wishes...

Okay, I think this is such an obvious concept that the developers themselves will come to it.
Sooner or later. Tool wheel is essential too.

Looks like I've found the solution. It's a Pie Menu plugin.
It would be great to have this functionality right «Out of the Box». This guy just did it the way it is implemented in Autodesk Maya.
The plugin allows you to almost completely abandon the keyboard. It's a big deal when you use a Drawing Tablet instead of a mouse.
It's even better to have Pop-up Palette for the brushes and Marking Menu for the Tools.