I'd love to see just 2 as long as somebody had been evicted the previous night. They should include the day leading up to the finale in that show as well as spending more time talking to each past housemate and look back on the series overall. Also some time talking to the last 2's friends and family i agree that it would be good seeing Davina go into the house and interview the final 2 together i then think they should leave together and the winner be announced outside then a second brief interview with the winner. The thing i dislike the most about the current finale shows is that they are dominated by eviction interviews.
Basically I'm wanting a more bbau style finale i especially love this part
http://www.youtube.com/watch?v=LESqv6Mk5mk