Dave:
agreed that lateral symmetry is functional beauty, but simplicity of design is also a good principle.
Not much has touched the single main rotor / tail rotor for overall simplicity and functionality for small helicopters.
For larger ones, options like tandem and co-axial are viable, but there must be a good reason besides marketing why the overwhelming majority of small helicopters are fitted with tail rotors.
There has to be a reason for it, perhaps we just don't know all the tradeoffs.
Shawn