Depends on your definition of invasion. What Gaius did now was pretty low scale compared to Nael van Darnus's attack.
Do you think it is possible that Varis will come to Eorzea to personally adress the city state leaders? Would be a nice little gesture. And it's not like he has any prominent generals to use as Nael, Gais, Livia and Rhytatin are dead, and Nero pretty much went rogue.