A design made of only lines can be successful as long as both the lines and the gaps between are not too fine or small.
With every client there may be unique letter combinations together with their corporate activity, ideals or name that can allow a truly great identity.
Breaking solid shapes into discrete, separate shapes is a valuable tool for logo design.
Planar shapes represent shadows with solid shapes. Silhouettes show an overall contour with solid shapes. Both techniques can make good logos.
Containment can be as shallow as putting a shape around a signature or it can be the saving grace of a good design.
People think that constraints limit creativity. The truth is that real creativity only flourishes with constraints.
In both the print and the digital world, tiny elements or fine lines cause real problems in logos.
The word "design" implies care in rendering. There is no place for sloppy work in identity design.
Overlapped elements was common more than a hundred years ago but those companies figured out that it reduced legibility. It still does.
Any part that does fit with the other parts is wayward. It may also create the wrong mood for the company.