Trust me, you don’t want a roof. The roof at Marvel is extremely unpopular. A metal roof create shadows which broadcasters hate - hence why the Marvel roof is closed even on a dry 20 degree day. Watching sport in the middle of the day indoors with lights on creates a very strange atmosphere. Most don’t like it. And a clear roof create a hothouse effect, making it unbearable in summer. They will regret the door down in Hobart. Waste of $250m.
Also, there is no way Sydney would host all of Taylor Swift’s shows just because of a roof. Melbourne was her biggest crowds ever.