page 8 in the RRG:
"In a campaign, players are limited to the number of figures included in the game. For example, the Imperial player is limited to six regular and three elite Stormtrooper figures, even if he owns multiple copies of the game."
This definitely needs to be changed!
It seems to imply that players cannot use new expansions in their games!
It means that Rebel players cannot try using newer heroes or newer allies in older campaigns and that the Imperial player cannot use new bad guys like Heavy Stormtroopers and Rodian hired guns in open groups.
I understand the spirit of the rule was to prevent the Imperial player from swamping the Rebel heroes with impossible swarms of cheap Stormtroopers. My proposal will respect that spirit and allow new characters to be played:
"In any campaign mission, the Imperial player is limited to one elite copy and two regular copies of any one specific non-unique deployment card. This total is spread throughout the initial, reserved, and open groups. For example, if the Imperial player has an elite Stormtrooper in the initial group and one regular Stormtrooper in the reserved group, then only one regular Stormtrooper may be chosen for the open group."
Please like this post if you agree that this would make a good errata. IMHO, I think it does retain the spirit of the old rule without the restriction of never being allowed to use new expansions in your campaigns.
It's also an easy rule to remember because it's exactly half of the skirmish mode limitation of two elites and four regulars of any one non-unique deployment card.