All helicopters are a compromise, weight,complexity, cost. The 169 has clearly been built down to a weight. Hence the hundreds of titanium panel screws. Around 30 euro per screw.
The basic design philosophy for the duplex bearing is sound. The 139 hit 2 million flying hours, two and a half years ago with no undetected failures. So it is not unreasonable to use this system.
All helicopters have multiple areas where a single failure will cause the loss of the aircraft, if you design them all out the aircraft goes nowhere due to weight constraints bought on by duplication.
At the moment we have the tail servo mod, however, I am sure that a redesign is on the cards. This is not a quick fix and will require re-certification.
The idea of a second bearing at the input end of the control shaft seems a good one.
Helicopters tend to evolve and few have entered service without at least one major defect.
Worth remembering that more than one S76 was lost due to tail rotor control failure, main rotor head failure, not to mention engines chucking out turbine wheels. In comparison so far the 169 has seen a better introduction to service.