A recent editorial in World Architecture News says that the controversy about the Ara Pacis Museum possible being razed is quieting down:

Mary Lou Bunn, a communications spokesperson for Richard Meier's office said, "things have been quiet" (since the announcement was made). She added that Meier "is willing to talk to the Mayor" about the matter and that "people at the firm are very attached to the project." Ms. Bunn said that the Italian daily, the Corriere della Sera, had polled its readers about the matter with the results being that somewhere near 70% of respondents want the building to stay.

As I stated earlier, I think the odds of anything happening to this museum are close to zero. It is simple populist politics to make statements like Alemmano did, which the Italians are quite good at. At the same time, the article quotes a poll by Corriere della Sera showing that the "people" want the building to stay. There are other papers in Italy that if polled would probably show the opposite.