If you ever want to add Russian Empire...

[Alpharius 0]

It'd be better to have Red Army as a "russian" faction, as they've not only fought against almost everyone during the intervention of 1918-1921 (which will leave more space for maps and factions on them), but they are much more iconic than tsar's army. At least they are a bit more distinctive in terms of uniforms and colors. 

For example, where else you would see an iconic hat "buddenovka" with a big red/blue star on it?

 

 

Whereas Emperor's army of early WW1 are quite unremarkable and barely differentiate from other countries' armies (except for american with those big ranger hats ofc).

 

To sum up: while technologically empire's army and Red Army are not different (they both used HMG "Maxim", mosin nagant rifles, nagant revolvers etc), Red Army is much more iconic and distinctive, it had more diverse enemies and places to fight, and you might be the first ones to ever add early Red Army to a game.

 

[FM. HezzyBear 13]

see i liked what battlefield 1 did where they portrayed the civil war between both parties. would love to see that in BTW as also the americans were involved and what not so could make a few interesting battles