Hi,
some observations:
1) Wireframe view is very poor. Most of lines are not visible why is that, will it be improved? Wireframe view is important meanwhile 2d drawing - later in point 2.
2) While creating new drawing everything should go straight into wireframe view mode or all other objects should be very transparent. It is hard to sketch when everything is covered by solids.
3) There should be a key assigned to selection in that way, when one solid/planes is covering other one then by holding pressed for example "tab" button you will be able to select item behind.
What do you think?