I also vote for a native section tool extended to solid-group.
As to keep it simple, it should render solid-sections only on solid-groups.
No need to implement additionnal contextual window for the optional material render style of the solid group, just use the same paramaters as cut-edge color, in style option. The advanced options to choose special material on sections are naturally an extension...
One other request : it could be really cool to enable easy partial section (only one side of a symetry axis for example), broken section (X parallels planes), and pie section by :
1) Right click on a section plane, to acces to context menu option "divide section plane"
2) Select, then move one side to make a broken section
2b) Select, then rotate one side to make a pie section
2c) Select, then delete one side to make a partial section...
In fact I am often making big buildings model, with lot of groups.
It appears that making a pie section within a big construction tree is really awfull.
If I want a clean and flexible result, I do multiple copy of the groups and various section cuts within... And if I want it quick, I use Zorro, erase, and then cleanup, but it's still dirty work and destructive modeling...
A better section tool could really be usefull.