Note that players tend to identify with the sides they're playing, so a game should allow for as much personalization as possible. On the other hand, some scenarios derive part of their flavor from predefinitions. For instance, a scenario with sides named "German" and "Russian", with appropriate colors and emblems, doesn't have quite the same feel when players rename them to "Subgenii" and "Simpsons".
A side can have a huge amount of state data, such as the current view. This rarely needs to be included in its entirety; synthesis methods will usually suffice to set view data correctly. Since total security is impossible with a predefined world, setting a side to have only a partial view won't necessarily be useful to keep players from knowing what that world really looks like.