I wouldn't rule out Rafa staying - if the terms are right for him and has some sort security with it.
I think this club, even if it spends one season out of the PL, can fulfil his vision ( I think it is anyway) of making NUFC 'his' club. Knowing him, he probably fantasises about being the first NUFCmanager of modern times to win us a trophy.
And I think some people underestimate the pull of NUFC - even under Ashley's disgraceful tenure.