You know, I've never really seen problems caused by people flying a 5 mile final. I'll do whatever minimises my track miles (not for financial reasons, just because I want to get home), more often than not this results in joining cross-wind or down-wind, but if a 5 mile final suits, I'll fly one.
I know that circuit traffic have right of way, but if I'm in the circuit and someone else is going via a 5 mile final, I'll slow down or extend downwind if they are ahead of me in terms of track miles to run, and if I'm going via a 5 mile final, I find the circuit traffic are always accommodating if I'm going to reach the threshold first. Everyone else seems to act the same way and it all works pretty well.