Much as it pains me to say this, it's a hugely difficult job that can only be done by very bright individuals*. FCs have to have good situational awareness and the ability to think in 3D at supersonic speeds, they also have to be able to manage tactical assets in constantly changing situations. It’s harder (IMO) than being ATC -But I'm sure Sir Toppam and Spotter FC can go into intricate detail
It's no longer true to say they spend all their time in the UK in bunkers, the future is mobile, with 1ACC, E-3s and whatever sensors become available being sent off to wherever that week's hot-spot happens to be. The world will be your lobster
With the new UCMP consoles it's not even necessary to work in the dark anymore!
*doesn’t necessarily mean they have many social skills