One player character type can even fly, has a scifi uniform, and sports a futuristic looking gun, yet the one recommended to new players is a random police officer who has been given an assault rifle. Why isn't it at least an infantryman? What a strange game.
So EDF 5 has you start out as a civilian, and it is several missions before you enlist and become a real soldier. But your security guard WILL become a proper infantryman... well, as proper as EDF gets.
Ranger IS the simplest of the four classes to pick up. The weapons are simple, and there's no advanced techniques or shared resources to worry about. Just point and shoot, and TRY not to unload the ten-barrel grenade launcher into your teammates. Learning to manage your reloads and mind the swarm is a lot lower-risk with the ranger.
Granted, I came into the series with EDF2017, so ranger was my ONLY option to learn the ropes. But I still think it's the best to start with.
Wing diver is fun as hell(and my preferred class), but only once you have a basic understanding of the game. Until you do, you're likely to spend a lot of time helpless because you overheated your reactor(which powers both your guns and your jetpack) in a melee and until the cooldown finishes you can't fly, dash, or shoot. And being helpless sucks. But once you have a feel for the mechanics and stage design, you are a winged harbinger, raining death upon all who oppose humanity at lightning speed(but somehow still slower than a fencer that's mastered dash-chaining at mach death incarnate).