No it isn't. 5th to 8th are a total waste of time.
The double chance isn't the problem IMHO - it's the week off. Statistically it's just super unlikely that anyone will win 4 straight finals where at least two teams get a week off and only have to play 3 finals.
It's not supposed to be easy. If you can't make the Top 4, you have to do it the hard way.
Normally to win it, a team in the Top 4 has to beat - during the finals, the other 3 Top 4 teams.
What could be better than that of proving who the best team is?
The romanticism of 5-8 battling to have a chance is there. You'll get rising teams, and fallen champions having one last shot in those spots. Why would you have a problem with that?
It's not like we can put teams in 5th-8th into some Continental competition - which is what occurs in Europe. You would make it a Final 4 again and destroy crowds in the second half of the year?
Idiotic idea.