I would prefer a modern shelter to an old ROC post, but would prefer an ROC post to being on the surface or in a lightly built house during any future emergency.
I know of someone who has a private fallout shelter attached to their house. Clearly based on the design of the ROC posts but larger, it consists of two rooms or chambers joined in a right angle formation, each room is the same height and width as an ROC post but twice the length.
"L" shaped in total, one end has a standard ROC style shaft and ladder from the garden, the other end has a secure and blast resistant door into the basement of the house.
It is equipped with bunks for 8 people and stocked with food and water for 8 persons for a month. It is wired for mains electricity which is unlikely to be available during any serious emergency, but a battery charger, sump pump, dehumidifier, and mains lighting are useful whilst times are normal.
Returning to ROC posts in general, I agree that these should have been kept in good condition for any future emergency. We know not what the future holds, but better to be prepared than not. Hopefully more up to date facilities are now available, but the cost of retaining ROC posts and keeping them in good condition in addition to any newer facilities would have been trivial.
A regrettable number of posts on these forums refer to decommissioned civil defence facilities, no harm in exploring same and reporting, but I would have preferred that such places had remained secret, secure, stocked and maintained, and available for the next war.
I must stress that my criticism is of those who have closed, decommissioned, or abandoned such facilities, no criticism whatsoever is intended of those who explore, photograph and report.