It was the State.
The city is still planning to make all of Public Square a park. Cutting off Superior and Ontario will make it a pain in the keister to get to the Justice Center from the highway. And there are already three parks north of Lakeside (not counting Voinovich on the shoreline). Some of the ideas for downtown seem pretty dumb to me.
Closing the square to traffic would not cut off Ontario and Superior. There are feeder roads that bypass the square now and could be expanded to handle additional traffic.
If you are going anywhere near the Square to get to the Justice Center I would advise a different approach. The Justice Center is on Lakeside. Several blocks North of Public Square.
The traffic pattern now causes the square to be unkempt as it is a large bus stop for RTA. Closing the Square would create a much better atmosphere and a great place for all sorts of activities.
As for the State it is the least ornate of all the theatres and always has been. Try the Palace or the new Hanna.