As has been mentioned several times, SOU-GVA is operated by easyJet Switzerland, which has its own team of route strategists. easyJet Switzerland flies to several destinations not served by easyJet UK, and given the close proximity of SOU to both BRS and LGW, I doubt that easyJet UK will commence any routes from SOU in the near future. It is also worth noting that even if easyJet were to add more routes from SOU, they would have to be from one of the 22 operating bases that aren't located in the South of England. There is no chance that easyJet would commence a non-base route.