Hi great start! I love the UI design methodology.

Some modeling things I'd love to see:

ability to move the bottom right edit panel to the top / make it floating
ability to move modifier circle on the left / make it floating
Edge cut tool
wireframe or faceted shading with wireframe shader modes
double click edges to select edge loop
a toggle which always checks for creation for non manifold mesh after edit operations
non destructive modifier for subdivision
non destructive modifier for Mirror mode
expose vertex size setting and option to change to circle
improve obj import support , some triangle errors and crashes on moderately sized files (250 MB files)