And therein lies the problem. Rail staff are only human, and the natural reaction when something happens is to sort it out as quickly as possible. Trying to provide a running commentary to the wider world takes almost as much effort, and usually there's nobody to do it.
Part of the problem appears to be structural. The disruption information should be on both NRES and the FGW website - when one is updated, so is the other, this hasn't happened.
They had staff on social media duties, so there are the staff time available. A more useful use of their time would be to firstly ensure the public information is up-to-date.
I think there is also a strong argument for giving more information about the problem. For example, during the previous flood an embankment between Bristol Parkway and Swindon was damaged. The plan appeared to be to cancel most Cardiff services, and just run the Swanseas, with trains being diverted via. Bath. Making such information public (and indeed, the guards' on-train announcements did a good job in stating the actual problems) would be a good idea, rather than a vague promise of delays and cancellations.
The disruption page only usually only got updated in the morning - an update in the evening about plans for the next day (even if the information is incomplete, and a disclaimer was provided), would be a very good idea.
It's clear to me that FGW/NR did a good job in fixing things and in utilizing the working infrastructure as effectively as possible. It's frustrating that the information being provided, which is the easier thing to get right, didn't reflect this.