Honestly, who really cares. If TF2 is as bad as everyone says it is, and the public agrees (I thought it was terrible), then TF3 won't have a record opening, it won't cross 400 million, and it won't do nearly as well as TF2 did. That said, TF2 WILL NOT touch DMC, and there is no chance in hell it will reach 450 million. Even 400 million is not a lock.
That said, if you want to see bad WOM at work, just look at Bruno's drop. If you want to see a bad drop for a blockbuster film, just look at every single HP film. A 60% drop is bad, but, going into its 3rd and 4th weekend, SM3 had drops of around 50%, which is worse than TF2. HBP's chances of hitting 300 million are around the same as TF2's chances of hitting 400 million, just because of how insanely frontloaded the series is.
Anyways, all the TF2 haters can rest easy knowing that Bay won't even have the biggest film of the year, domestic or worldwide.