Let us imagine a two-way bonus/penalty system. Spear-based infantry, for example, might have the conventional RTS bonus of, say, 1.2x attack against cavalry. To most people it would be common sense, and I'm sure you don't want a speech bubble around each spearman saying "I have a bonus against cavalry." Now, then, you could also have the X formation, a nice icon of raised spears, a help bubble (รก la AOM) detailing its additional bonus against cavalry, but penalty against archers. A newbie not using formations to his advantage is simply like not using unit stances to his advantage; one would have to pick up on it. Also, I don't know how fast-paced 0AD combat is, but if it's going to have things like formations, it'll have to be a *bit* slower than the AOM/WCIII line.