I don't think the long campaigns have enough oversight between missions to balance things out based on THIS campaign. Currently, the rewards only consider who won this mission, and not how many missions have been won or lost in a row so far...
I don't think it's enough to adjust things based on the outcome of each mission individually - there needs to be a programmed oversight of the campaign as a whole, serving to mitigate the snowballing of power to one side. This oversight would address the issue of 'talent' on both sides of the table. Kinda like skill-based matchmaking in video games. You get stomped in a couple games, you get matched with lower-skilled players until you win one, then things even out for the most part...
It's possible for a good IP to steamroll average players every mission - but if they win 2 in a row, maybe the losing side needs an injection of power. Then, after that injection, if they lose yet again, they would get a greater injection until they manage to win. The campaign design should be doing everything it can to keep the ratios close throughout a campaign.
It might be 'fun' in the 'pew pew' sort of way, but it will eat an anyone to lose 7 missions in a row - I don't care who you are...