In the Trib this evening a very detailed article was posted. It discusses the present landmark status elements, which to my surprise includes the exposed steel columns and overall height.
The ordinance does not shut out changes which includes the seats themselves and configuration. More advertising has been added in the concourses
Of most interest is if the upper deck is razed, there is a motivation to increase the mezzanine skyboxes to the point where a new upper deck would be higher.
ISFA is expecting renovations to be $350-400B; that's up to 2/3rds of the cost of the catastrophy that occured at 16th and Balbo.
They also compare/contrast to Fenway and that Fenway is in the pending state for landmark status. There appears to be a good faith agreement in bean town that may or may not be present here in the windy city.
So it remains to me at least, that the landmark ordinance may not have to be relaxed as a whole, only in parts, and significant changes can occur.
From this it appears there will come many a proposals on how to get around or alter the landmark status points. It really looks like things are going full speed ahead folks.