If this movie is anything other than excellent, it will bomb.
Almost everyone will view this as a sequel despite what some people on this board think.
Unfortunately the last movie, followed a box office pattern that bodes poorly for sequels. It had lots of buzz with an excellent opening, but then plummeted on poor word of mouth. (Nearly 50% of it's B.O. was on the opening weekend).
Movies like the Bourne Identity, Batman Begins, The Matrix, POTC, followed patterns that bode very well for future sequels. Decent opening, followed by good word of mouth and a long run in the theaters (BB's opening weekend accounted for less than 25% of it's B.O.)
So with the very poor trending of the Ang Lee film, and the general public impression that this film is a sequel to that one, I do anticipate a lackluster opening for this film (same as what happened to Batman Begins following in the wake of B&R).
Now if the film turns out to be excellent, word of mouth can give the film legs and it can hopefully follow the BB pattern and pull in a respectable B.O. over the summer. This would redeem the franchise and put it in a good position for a sequel.
However, it the film is anything other than excellent, it will likely follow the typical pattern of this genre to be front loaded. That means an end return of 2-3 times opening weekend based on how well it is received.
Even a 2.5 return on a 50M opening would probably be received as disappointment.
So to summarize, if the film is excellent it will be a sleeper.
I think being a hit is very unlikely.
I've got my fingers crossed that it surprises me (in a good way).