There seems to be a lot of people focusing solely on the Hitachi situation as being the reason he has left.
Actually, there's a lot more to it than that. Yes, the Aurora roll out hasn't gone to plan and everyone can see that and also see that it is not necessarily the fault of EMR or its people.
So why has he gone?
If we look at the wider state of affairs, there are wholly credible underlying safety concerns with the Auroras but yet the company appear to have dismissed these claims and continue to push out units in daily service with known repeat faults and failures. Safety IS the line. It shouldn't be bent to suit operational desire. Any other fleets and similar industries would "ground" a fleet until potential for safety issues to reoccur were resolved. If it's Hitachi's fault then they should pay the associated costs of hiring any replacements etc. EMR have failed to resolve this long standing issue and have jeopardised safety.
Similarly, have a look at the regional and connect fleets. In some cases, they are literally falling to bits. Maintenance has been been so bad and I've never travelled on another TOC ever that has been as slow to rectify such obvious cosmetic faults. Now imagine what it's like for train crews reporting faults that the public can't see. In a lot of scenarios, what the public can't see is even worse.
Regional provision of services is inadequate and has been getting worse during the tenure of EMR. Under stagecoach EMT, units were clearly maintained to a better standard and reliability was evidently much better. There was more of a mantra that services HAVE to run. Regional services are now commonly cancelled, and in comparison to some other TOCs, not usually for crew issues. It is most likely a service is cancelled these days due to unit failure or even lack of units. The units that are out working will have questionable adherence to regulatory standards.
Staff morale is at an all time low and the MD was the least visible, least approachable and most far removed from the reality of what goes on, for at least a decade, if not longer. So no, it's not all about the Auroras, and talk to the staff, the real staff onboard, no he won't be missed by many within the company.