Original and familiar are not contradictory terms. Take a look at the redesign of the Mustang, for instance. Both are different cars, but they still have the same 'feel' to it: What you need is something that people will recognize as a coffin. That's the most essential part. Originality is actually a secondary goal.…
First of all: be more daring. I wouldn't really considering moving 1 line a 'new design'. Primitives are 'basic shapes' in the 3D world. Things like rectangles, spheres, cylinders etc. Basically - you're not making interesting shapes, you're just using a few simple ones. What I'm gonna say next may sound contradictory, but…