I have started to use Part Design and therefore the Sketcher a lot.
I would suggest that some of the controls get re-arranged so that:
1. Things that tend to be static are grouped into a sub-tab.
2. Different things that have dynamic/arbitrary long lists of properties e.g. Constraints and Elements get their own sub-tab so that they are not limited to be included in a view with several sub windows - also those sub-windows are currently limited to only show about 7 lines of information - feels like configuring/amending Windows in an old-style way - e.g. network configuration.
Sketcher / 'Solver Messages' specific: I would suggest a better visualization of 'Elements' having constraint issues - often it is confusing or requires too many clicks to find the information - e.g. bringing the solver message close to the views of the constraint and elements lists e.g. highlighting these directly and maybe use small icons to indicate over or under constraints could help to quicker find where problems have arisen.
Currently I use two monitors to kind of being able to keep track of things even though it is not totally ideal.
Attached as it looks in FreeCAD 0.18.4. (Notice 'Solver Messages' sub-window I have left out intentionally. It could be categorized to belong to the static group of options, but the message(s) could definitely go close together with the lists of Constraints and Elements.