The Imperial Army Trooper is a unit available to the Imperial Remnant in all eras. They cost 200 credits, need a Barracks to allow recruitment and you get 5 squads of 9 members per company. Each trooper is armed with an E-11 blaster carbine.
While the Stormtrooper Corp was the image of the imperial infantryman thought Imperial space, in his shiny white armor, menacing looking helmet and clutching the ubiquitous E-11 carbine, they were seen as an elite unit. As the name implies, they are shock troops, meant to act as the tip of the spear applying pressure supported by heavy weapons and vehicles onto a weak point in the enemy lines and punching through to wreck havoc behind enemy lines. Once this was done it was the job of the humble Army Trooper to mop up enemy resistance left behind the main assault and to establish and garrison field bases and defenses.
The Imperial Army was the most numerous land-based military institution the Empire possessed and it´s main job was to garrison the myriad of worlds that it claimed over. Recruiting or conscripting from each of it´s worlds. If the recruit passed the basic psychological and physical test he was to be assigned to one of the thousand of drop camps all over Imperial Space, where his basic training would begin. Weapons training, basic team building exercises and physical training would shape this recruits into a professional and effective fighting force, if lacking in experience and morale.
In-game use Edit
Other than the novelty of using Army Troopers instead of the widely more famous stormtroopers, this unit´s only function is to work as cannon fodder or distractions, if that. They do nothing a stormtrooper company wouldn't do better, they don't have heavy weapons or specialists (All the members of all squads are riflemen), they don't have buff giving officers of any kind, they can't fire on the move and they aren't particularly efficient as being garrisons since they do everything else regular infantry troops can do.
In short, unless you really want to see them or use them, get stormtroopers.