I know this season the A-League title went down to the wire but generally speaking the competition needs the finals system to keep people's interest during the regular season.
There have been seasons in the past where the title has been pretty much decided with a third of the season to go. Imagine if there was no finals system? There would be a third of the season remaining and literally no one would be interested. At least in the Premier League when there's a runaway leader we have the fight for European places and avoiding relegation.
I get why people don't like it and I'd hate to see it in any of the big European leagues but a finals system in the A-League is a good thing in my opinion.