This is all reminiscent of other TOCs when they had insufficient staff for weekend services and would bin off the services on the day, rather than cancel beforehand.
That is my major criticism. Over optimistic rostering. In summer if you are likely to be short two to three weeks out, you probably will be on the day so cancel the trains well before the day, not on the day itself. If that means you have spare train crew staff, well that helps you manage the on the day shortages.
In terms of the long distance TOCs, GWR and LNER have enough staff to deliver the current service, Cross Country and East Midlands are almost in the same position but Avanti and TPE haven’t enough staff and what makes those two even worse is their tight diagramming and, in the case of TPE, tight route knowledge. So when it goes wrong, it really goes wrong! Staff also get worn down quicker if they are racing around.
GWR were in exactly the same position as Avanti until they could recruit enough staff (the DfT authorised a huge increase in drivers there) and, irrespective of who is in charge of the TOC, until Avanti get into the position of having enough productive staff, it is going to be grim.
Personally I would abandon this DfT inspired quest for the ultimate in train crew efficiency (they go through your diagrams before or even after award to try and reduce the numbers) which FG has been rather too good at and go back to what happened in a couple of previous franchise competitions where a minimum number of train crew, by grade, had to employed at any one time.