The SCG is just not suitable for a rectangle game in this day and age.
I don't understand why it can't be a fluid thing. If two QLD teams reach the grand final it gets played at Suncorp, if a NSW team make it and QLD or Storm then play it in NSW, and if a QLD team and Storm make it then it be held at either Suncorp or AAMI decided by which team finished the regular season higher up the ladder. That way NSW keep priority in the likely event a NSW team make it each year, but if it so happens there isn't a NSW team it can be played where the fans are instead of having ANZ half empty for say a Cowboys Titans grand final
It's always been is Sydney.. so keep it here... if Queensland want a grandfinal to be played there.. then start a new competition... Nswrl will die if it ever goes up there...