I adamantly believe that the Imperial Guard should be an independent faction, not just cannon fodder for the Space Marines. Because all must feel the might of the Leman Russ Battle Tank. A Baneblade would be nice too, but that would probably be OP.
Much as I don't care about the Guard they do deserve their own faction they're not cannon fodder.....yet.
Strictly speaking, Imperial Guard are basically used as a human steamroller. They're sent out in huge numbers because the Imperium can always find replacements with relative ease. You forget; this is a galactic-wide government that can sometimes loose track of entire regiments because one of the Administratum made an error in paperwork. As has been said "We measure our strength not in men, but in planets". Therefore it makes sense for them to be a cannon-fodder unit. However, I also agree that they deserve their own faction. They're certainly significant enough in-universe and popular enough out-of-universe to warrant it.
It's very easy to make subfactions for the other races as well. Exodites for Eldar, Chaos Undivided for Chaos, Blood Axes for Orkz. Expanding a faction with more classes and models and art pieces isn't really that hard. As far as the perception of OP is concerned, you're forgetting the losing factions can always decide to work together to take down the winning faction, whoever it is. And there's always the 'Nids, which will glom onto anyone's territory until you kick them out, meaning that the more you're winning, the more 'Nids you have to deal with. Also, I don't appreciate your condescension.
But at the end of the day the IoM will still have the most because Exodites don't really work and the things you mention just already exist. Yeah make a faction that size and they won't need to worry about Tyranids.
Before you go off claiming that creating huge, branching factions for all the races. I suggest you learn a little bit of code and learn just how much time is needed to do some of the simplest things.
When I said "easy" I didn't mean in the programming sense, but in the explanation sense. It's explainable why the factions are the way they are, but I never intended to mean it was not difficult or time consuming to implement.
