This work mostly takes a couple of two column areas (pen sensors and auto brush tip areas) and makes them into a one column format. After doing this, a ton of other settings and properties needed to be adjusted.
The final result means a much slimmer brush settings area.
In addition to condensing those areas, I also organized the brush configuration options to its own area. This is located from a pop-out menu on the top right of the settings. Configuration settings are things that aren't necessarily saved to the brush, but affect all brush presets.
The last bit is just allowing the live preview area to be hidden, as well as the height of the widget be adjustable. There was an illustrator I talked with recently over email "Zhille" who requested that the current brush preview is too small for painting brushes.
If you want to see a better break-down of the changs, visit the petrovic/brush-editor-condense branch. That has all this work.
Original wireframes and discussion were done here for this: https://phabricator.kde.org/M137