2 might be company, and 3 a crowd, but is it really enough for a daily scheduled air link? Still, the point about route combinations is interesting. EZ pulled out of LGW to ZRH due to a landing fees dispute. Would that have previously been acceptable to the men in suits? Probably not, because of no guarantee on connections + frequency issues.
Flybe have dropped SOU to GVA, or is this just seasonal? So I'd guess that Flybe to BHX and then Swiss to ZRH would be the shortest route which avoids crossing between airports?