The reason Gus want's this game more is for his own personal reasons. I personally know a highly ranked member of staff within st mary's (family friend), who stated that Gus was one of the three names on our shortlist, along with Howe and Adkins. Adkins got the job, which Gus was not at all impressed with and since has held a personal grudge with Cortese. I don't believe he dislikes the club, I believe it is Cortese that he is wanting to get one over on.
Don't take this as gospel as I don't know if this is 100% correct, however I wouldn't doubt my contact so expect that this is very, very likely. For Gus, Saint's, so long as Cortese is in charge will be the club he want's to get one over.
I've heard this from a Saints man in the know also.