This is based on musing on the game's balance more than anything so it really would be more of a general guideline as opposed to anything like an actual game balance.

The three factions are; Military, Militia, Colonist

Military
Scouts = Recon Troopers (RT) [ex. RT Williams], emphasis on poor visibility spotting methods [ex. thermal/low light/ragnite emissions] with a more powerful rifle with modestly reduced accuracy.

Shocktroopers = Stormtroopers (ST) [ex. ST Williams], greater emphasis on armor and suppressive fire with a large number of shots (30-40) available between reloads. Also, 2 spiked stick grenades.

Lancers = Arc Lancers (AL) [ex. you get the idea.], having a reduced number of shots (2) but far greater power and also modest obstacle piercing capability, these have abandoned any semblance of projectile technology and fire blasts of concentrated electricity (think of a bunch of lightning bolts braided together and bent into a thin oval. That's the general look I had in mind for the shot.)

Snipers = Sniper (S) [ex. some things don't change.], the military has embraced alternate munitions wholeheartedly with its snipers, going so far as to accept reduced range and power, their snipers are now trained to avoid headshots in favor of delivering status altering rounds more consistently with shots into the center of mass.

Engineers = Maintenance Trooper (MT) [ex. yep, all jokes get old], due to the ridiculous rate of engineer casualties over the generations, the military decided to add additional armor and remove the ragnaid. These more powerful ragnaid modules are now attached to the rear of most armored vehicles and can be accessed by any soldier, especially the MT hiding behind the tank in an effort to keep it running. They share the same rifle characteristics as RT.

Militia
(Denied the title "soldier" by Imperial Decree some hundred years ago to preserve the inflated ego of the "Ever Victorious Imperial Legions", these forces are spread thinly and serve to protect the civilian population and more significant colonial settlements and infrastructure from local threats and, on occasion, popular unrest.)

Scouts = Scout, with an emphasis on range and accuracy, this class of militia is also equipped with transmitters and com-links along with the best in light fabric armor. While their rifles only have three shots per reload, their power, armor piercing, and accuracy are notably increased for dealing with large predators in remote areas.

Shocktroopers = Gunners, armed with long range, accurate, LMG type weapons, these militia fighters carry no other equipment but have the mobility to almost keep up with scouts.

Lancers =

Snipers = Sharpshooters, denied access to true sniper rifles, these fighters carry customized versions of scout rifles. they have reduced range but still can reach farther than standard scout rifles. They fire projectiles similar to a HEAT shell, but smaller, effective against light vehicle armor.

Engineers = Engineers, these infrastructure and support experts are now equipped with deployable repulsion beacons which generate hard cover from a ragnite radiation field. This field lasts only ten minutes but the device can be collected, charged, and deployed again. Militia Engineers still carry ragnaid and scout rifles.

Colonist
(A combination of hopeful pioneers, minor criminals, social undesirables and undiplomatic prodigies, colonists come from almost everywhere and spend the rest of their lives taming the wildest and most dangerous territories for the Empire. Their children can never enter the Empire's "Civilized Lands".)

Scout = Hunters

Shocktrooper =

Lancer = Prospectors, using modified versions of Arc Lancer weaponry, these rough individuals blast deep holes into stone to check for the presence of ores more valuable to the colonists than the Empire.

Sniper =

Engineer =