Crosscountry's biggest 5 problems currently are IMHO:
1. Lack of capacity.
2. Too many passengers wanting to travel on very short trains.
3. Trains which are too short.
4. Overcrowding due to demand exceeding supply, often as much during off-peak as during the peak.
5. Trains with a lack of seats for the number of people wanting to travel.
Some people may notice a theme in the above points.
The ageing nature of the seat covers is a lesser concern for most travellers. That's not to say it isn't a valid point, just that it would be nice to say it was the worst thing about XC journeys...