>>6929545ProTip: Aiming allows you to kill the thing you're shooting at.
that guy in your pic? HE's not actually shooting at anything right there, and likely standing way above it to get a better look at what's in front of him. IT's like when a tank driver is sticking his head out of his hatch when he's doing donuts in a sandbox, instead of sitting inside his cramped cabin, looking through mirrors, while in combat.
So that guy standing outside, exposing his entire upper body? He'll be standing lower, with his eyes looking almostly directly down the barrel of his gun, concentrating pretty hard, looking down the sights, protected by armored plates on either side and maybe the front, to fuck up some guy's day.
And you're right, the warthog is ridiculously sized, mostly because Bungie realized how silly 7'2" Master Chief would look sitting inside a cab made for 5'10" manlets. Just like all of the guns the Spartans used in the game are especially made for the Spartans, because they're made in proportion for tall ass giants in armor, instead of looking like puny normal soldier toy guns they could fire one handed.
So those Figmas? They're actually taller than Master Chief is, so maybe 9' tall, if they were actually to scale with that Warthog.