no, the demise of the GOP is definitely not a good thing.
moderates will continue their exit, leaving the party firmly and fully in the Christian Right. The Christian Right GOP will pick Palin for 2012, Obama wins 70% of the popular vote.
Two possibilities after the 2012 landslide:
#1. moderate Republicans regroup and form a new party of the center. GOP stays and linger on as a fringe party.
#2. moderate Republicans retake the party after the complete collapse, re-establishing the two party system.