Dave,
You are looking at it with the right set of glasses, we call the N/Rev disturbences "root shears" to mark their equivilent vertical and in-plane vibratory shear force acting on the head. These have strong content that varies with the number of blades, so that going from 2 to 3 or 3 to 4 blades makes a non-linear improvement on the size of the root shears. The root shear magnitude drops markedly due to the number of blades, and its frequency rises at the same time, making the net effect a reduction in root shear effect that is not quite N squared (so that 4 blades has something like 15% of the vibration of 2 blades.)
The root shears rise due to the rigidity of the blade attachment (since the blade can't flap or hunt to relieve some of this shear mechanically.) Thus, your hope that an awsomely rigid blade would be immune to N/rev vibration is actually backwards. Most of the time, we try to tune the blade to be compliant (softer) in a given frequency where it can help relieve these vibrations or absorb them.
The response of the fuselage is important to vibration supression. The low N/rev frequency of a 2 bladed rotor is a problem all by itself, because as the frequency drops, more things on the aircraft "like" that frequency, and try to resonate at it. This makes the ride quality much worse, of course. Also, as fuselages get bigger, their natural frequencies drop, so they need more vibration treatment.
All rotors produce N/rev, it is not a sign of a poor rotor. Pilots have this mythological belief that if they feel an N/rev, there must be something unhappy in the rotor, or it needs redesigning. Actually, all rotors give off about the same vibration (based on the number of blades, the hinge offset and the rpm) but what you feel is a measure of how well the manufacturer has learned to hide it or absorb it, or how the place where your seat is bolted is responding to it. It is possible for a complex airframe to have variability of 5 to 1 depending on where the seat is attached.