I'm not sure the through roads at Nottingham would have helped in this situation. As someone has posted, if the train had been brought into the station it would still have tailed back over most of the east end throat, and this would be the same whether in a through road or a platform. A long loop east of the station would have helped, but there probably isn't space for one.
As someone has suggested, the best idea would be to make sure that whoever just has route knowledge east of Nottingham also extends signs as far as Beeston so the train can be dumped on the Up Slow or Beeston yard if unable to go forward.
I agree the layout at Nottingham isn't too logical, although it does seem to have reduced waits at the station - if a London arrival is a bit late it can pass the next London departure on the right rather than having to stand outside until the departure has cleared. With hindsight they should have built the platform 8 that they have made provision for, or at least the western half of it.