As long as they don't take the Paul Feig route and start insulting the audience (and their parents) it could be a passable (though not too interesting) movie.
Bullock is an excellent choice for a middle-of-the-road swashbuckler, and Helena Bonham Carter is kind of the female Johnny Depp. Hathaway and Catie are likely too boring to bring anything interesting to a lightweight, charm-based heistscene and then there's ....
I don't know what kind of cocaine-induced festivity preceded that decision, but it must have been a good one.
Hmm, this might be more fun if they cast everyone as a woman, including all the bad guys and everything. Just making it a movie about women, with women jokes and women thoughts and all. No bashing, no battle of the sexes, just a movie that appeals to women, thinks like women, and is all about the heist stuff.