During the 35 years in the wilderness I always said I didn't care if the GF was 2am if the Tiges are in it. Haven't changed my opinion even with our success in recent years. I was too pumped after this year's win to sleep anyway.
From the AFL's (and sponsors & TV execs) perspective $$$ will talk, so I don't see it going back to the traditional day GF given the ratings. They may push the start back an hour or so so that the cup and medal presentation isn't after 10pm.