Those already exist in the form of NOTAR, Twin rotor (Chinook) and contra-rotating MRs so it's not exactly ground breaking.
If it's not a good idea for the MR, why is it such a great one for thew TR?
Everyone would like to see a helicopter replacement that looks like a scaled up drone or quadcopter but to give it a useful payload is a long way from fruition.
Who said it was groundbreaking? NOTAR has its issues and advantages. As does Tandem, and coaxial, and contra... It doesn't have to be groundbreaking to be useful. This thread started because one poster was accused of trolling for suggesting an ETR... numerous others have weighed in that it isn't practical. In fact we now seem to have reached a point where it is, it's just a case of whether it offers sufficient advantage to move from the status quo. Are you unable to see the advantages of an ETR or is it having assessed it judge it isn't worth it?
I thought the reason to avoid the MR was covered in my earlier posts. That would be close enough to the all-electric aircraft, which I don't believe will look like a helicopter, so no point going down that branch - even if a continuously variable rotor has its attractions.
Quad, Quad tilt ... who knows what will emerge over the next 10 years?