I had professional dealings with them circa 2016/17 (not long after they won the franchise) and it appeared that they were wanting to change and improve things.

It looked like things were slowly starting to unravel and key members of staff brought in to support the changes, appeared to up sticks and leave quite quickly. 
Quite why that happened, I'm not 100% sure. Although it's not too hard to look at a time line of events and get a good idea of when things started to go wrong. 
* Strikes on Saturdays. 
* Customer Panel ceasing to function. 
* DOO issues. 
* Old stock. 
* Refurbs and associated stock pressures. 
* New stock not being delivered on time. 
* Timetable issues. 
* Issues with pathing for local connect services. 
* plus a boat load of other issues, including the arrival of interim members of staff within key management roles. 

When my professional dealings ended, I saw quite a poor level of performance from a passenger perspective. 
Complaints were ignored initially and refunds not granted. I was in the fortunate position to have the names of a few people internally and they pushed my complaints forward. 
Quite where others stood in the same situation, I am not sure. 

A rebrand has appeared to work for LNER, although they have the luxury of being able to offer more 'on board' and had the basics to help them on their way. 
I'm not sure whether a rebrand would work in this case.