The Phantom Menace was a huge success, far better then 2 & 3, even though it's considered the weakest of the 3 (though I personally think they got worse, not better) - because it was NEW STAR WARS (and it had Darth Maul). It will be huge. Being in 3D (with 3D upcharge) means it will be REAL huge. After the dust settles, faults may rise to the surface and those faults may hurt 8 & 9 to a degree, like what happened with 2 & 3's B.O. take.
The question as far as the financial success of the film is where it will end up ranking all time (not accounting for inflation). People are saying it can't possibly be less then the #1 film all time (and that that level of expected success is priced into $DIS). The question is this a film that needs to be seen again, and again, and again, and again, in the 3D format. When all is said and done I don't know if it will pass Jurassic World numbers once it leaves theatres. If that happens the stock may take a hit (though since it's seen as an ancilliary business by the Street it won't be as bad as the ESPN Correction).
And just saying - the Phantom Menace trailer was great....
And again just saying - Clones was considered superior to Phantom, yet it did less business then Spiderman.