In many, many years from now, when the sea levels rise and the coast of the UK is pushed further inland, the Dawlish Sea Wall will probably still be standing proud as a testament to the sheer amount of concrete poured into it over the last years or so. It will be fantastic to be able to walk all the way along the sea wall again. You don't realise how much you will miss something until you can't do it anymore. But what a feat of engineering and they certainly are doing a thorough job of it.
Hopefully it will be open again in time for the airshow.