Keep in mind the Splines are not situate centrally within the boundaries of the Thrust bearings balance points. There is a reason this powerplant is light, and 'efficient'. The two go together and rely on fine balance and gentle transition through the Thrust range.
Derg, in a nutshell, you have it. Within your parameters add Contra Rotation, higher Wheel Speeds, and ineffective EEC at failure boundary. There was a Punch List at introduction that should have undergone remediation prior to Service, IMO.
There were surmountable obstacles to be sure, but the time to address them is prior to On Wing Commercial service. Not cute to allow actual passengers to piggy back a development programme.