That would be a big mistake in my opinion. I can understand infrastructure and wht not is a big issue, but the location of Cairo will never change the importance of the city and whoever governs Cairo will have a big say in Egypt.
Perhaps expanding outwards and at the same time demolishing bad structures in Cairo could spreadout the crowdedness.
You’d need to establish a solid working group consisting of foreign consultants for Cairo. As city development left in the hands of domestic consultants seem to yield incompetence. I.e Istanbul in the hands of AKP.