I expect that SSH is there as a result of feedback from travel agents over the bridge it'll be curious to see if EZY respond to that.
Looking at route frequency and why certain routes arent there id suggest that Wizz wants to give people options of short breaks 10 day breaks as well as 7 and 14 day holidays hence why no gran canaria or summer lanzarote or Rhodes. It's likely those will be added if or when a 2nd aircraft gets based.