I have been following this in the news...
The deflagging was due to financial problems for the previous owner. He was unable to pay fees, pay off loans, etc., so Marriott pulled their name off the building, took the property out of the reservation system, etc.
It seemed very likely that the Marriott flag would return, but had not yet heard a timeline -- so a date of 12/12 is good news.
Marcus has promised significant renovations and upgrades, even though the property is still in pretty good shape already. (main problems seem to be wear and tear) There will be a new sports bar, which I believe will replace the main restaurant on the main level. There used to be a second restaurant on the second floor, so perhaps they will reopen that.
When choosing between the Cornhusker and the Courtyard: yes, the full Marriott will have more features, but it will likely have noise and disruption during renovations -- although there is plenty of construction *around* the Courtyard also. There is also less to do in the immediate area of the Cornhusker, while the Courtyard is much closer to the dining district.