The Zremesher is most useful when retopologizing objects of densely packed Delaunay triangulation or quad surface structure, typically after the sculpting process . Long thin triangles created from CAD applications, such as those associated with Sketchup, will usually present problem for any automated quadrangular mesh algorithm for exactly the reasons you've indicated, among other things. There just isn't enough surface information in such models for the algorithm to work properly. Using "guide splines" on the surface of the model before launching the tool can help the algorithm solve itself sometimes, but that is often not enough in itself to keep the result from being 100 percent efficient. Some form of manual editing will almost always be necessary after the automation is complete.

Personally, I almost always model from scratch using standard polygonal techniques and subdivision methods to avoid this problem down the road when working with hard surface objects. When it comes to sculpting detail in organic objects, I will usually do retopology manually as well. I actually enjoy the process of retopology, and find the tools relatively fast and efficient in packages like 3dcoat or 3dsmax, etc. In the rare case when I might do an automated retopo project, it's usually only on models where detailed sculpting has pushed the polygon count up into the astronomical range, and redistribution to a render or animation pipeline would be far too inefficient. In such cases, the objective right from the start is to sculpt fine detail in Zbrush or 3dCoat in order to extract nomal maps or other PBR maps to use on a low-resolution static base mesh anyway, so edge flow really doesn't matter.

______________________________________

My Store
My Free Models
My Video Tutorials
My CG Animations
Instagram: @luxxeon3d
Facebook: https://www.facebook.com/luxxeon