building a team around higher armor will most likely help.. remember that on average cairne will roll 5 successes of his 7 dice.. and unless the team is built around him getting an instant crit (which i can't imagine why it wouldn't in this game scenario) you probably won't end up losing a figure to the crit, if you can roll at least 2-3 successes in defence
however there are always those fluke games that even with a 4 armor character.. the cairne could roll a whopping 7 successes with crit and you flop on all 4 of your defence dice
but that's just the luck of the dice
that being said you shouldn't worry so much about the opposition as much as worrying about what kind of team you're going to build that can make quick kills with ease