I know, every campaign is different.
Far more important - even a single campaign can change from one to anther level of exceptional.
In Classic/Mega/TNE Traveller, PC's are only exceptional in motivation... NPCs, or at least significant ones, are explicitly to be generated by normal character gen. In fact, one of Marc's comments notes that characters dying in CharGen should be used as NPCs... But in campaign, while they won't gain much in skill, they can gain in fiscal, political and social capital and become rather exceptional... sometimes impacting way above their apparent means at campaign start.
Star Wars likewise... but the games for it really do encourage going from comparable to the average Template Rival, to becoming as potent as many storyline characters from the movies are written.
Meanwhile, In TSR-D&D, low level characters are pretty humble, but are, in fact, exceptional in a small way, since most NPCs have no class nor level; only clergy and guards are likely to be classed characters... but my mid to high levels, are supposed to be superbly exceptional ("Super-Hero")... Somehow, it fails to feel that way for me.
And in most supers games, exceptional is an understatement...