Forget politics, how about common sence?
I bet that the AF1 plane is pretty different from normal 747s.
I imagine there is enough amour to stop a 50 cal sniper rifle from penetrating the hull and giving the occupants a bad day.
I’d suggest that the plane is hardened against EMP from a nuke knocking out its systems. I’ll bet that the current 747 AF1 has more resemblance to the original 747 than it does with the current model. More mechanical devices will work after an EMP event than electronic ones. I’m sure that AF1 has lots of electronic fun on it, but I’ll bet it’s not in the flight systems.
Shielding for electronics adds more weight, plus your not guaranteed have your electronics survive. With mechanical systems, they will work even if they weigh more.
The choice of aircraft that AF1 is, I feel more to do with survivability than performance. Airbus may have a better aircraft, but it relies on electronics throughout. Can they be guaranteed to work after an EMP event?
Anyway, the President has no say on what make of aircraft AF1 is, it’s the people who have to protect him that dictate that.
I’m in the UK and I’d love to see the President flying around in an A380. But, for the reasons stated above, I doubt it would happen.