To be honest if I was booked to Fort William and diverted via Kingussie I wouldn't be unduly bothered. Assuming the Inverness portion was on time you'd get to Kingussie at 7.17 and its then a1hr 20 max in a coach through glorious scenery to arrive before time. The A86 isn't what I'd call a single track about 20 miles of it are 1 and a half lanes but it's not a slow road and under 50 miles between the stations.
Whenever I've suffered serious disruption I've always received a prompt full refund. Do wonder if some of the people on this forum aren't glass half empty people.
It wouldn’t be the end of the world, you’re right, and those of us who simply wanted/needed to be in Fort William for 10am would hardly care. However, it would fall short of expectations for those who wanted to do the Fort William sleeper specifically to enjoy the WHL and enjoy a leisurely breakfast in the lounge car crossing Rannoch Moor. That fickle premium tourist market is significant on the Fort William route. The A86 is probably a very lovely rural route but not quite the WHL that the tourists were sold.
The reason why a lot of complaints about CS are ‘glass half empty’ are that passengers paying premium fares have understandably high expectations, and understand (from the marketing) that they are paying for an ‘experience’ rather than just a train from A to B. In First Group days when you were paying for a bargain berth you didn’t expect much so were simply grateful to get there. At the end of the day, if you’d paid £75 for your ticket from Euston-Fort William, you’d probably cheerfully tolerate being put on a bus at Kingussie at 7.20. If you’d paid £300+ expecting the ‘journey of a night time’, you’d be somewhat more irate. That’s the difference, I’m afraid.
We seasoned CS users know that the ‘journey of a night time’ is just marketing speak which is undeliverable in practice, but occasional users swayed by the marketing definitely don’t. That, I think, is a huge source of complaints.