We are discussing on this thread buying the F18 E\F as a strike aircraft. Surely we need to be also thinking about some sort of air defence aircraft?
The US Navy consider the F18 E/F to be good enough as an air defence aircraft. It should probably therefore be good enough for us as well, in this post-"gold plating" era.
Having just 1 multi-role type embarked gives massively increased flexibility, allowing the proportion of aircraft assigned to DCA / OCA / CAS / AI etc to be varied according to the situation and not the availability of assets. This was one of the reasons why they tried strapping bombs to F14s and eventually retired them. We are also trying to reduce the number of different types we operate to economise on logistic support.