Nah, viewdistance slider was introduced with resistance, along with some other graphical options, like terrain detail. If you are playing in v1.46 or below, the viewdistance should be 800m (I think) for missions by default, unless the mission designer had chosen to limit that distance. In resistance, the player can choose his own viewdistance, although the mission editor can still "set" the view (until the player changes it). So if you have res, most likely you have somehow lowered your viewdistance slider.
Also, keep in mind that fog (a weather effect separate from view distance) can also limit your view, and looks about the same. So that might be the problem in certain missions.