Paul Feig talks Bridesmaids sequel with Vanity Fair. There's been some talk that the studio would do a sequel even if it meant not having Kristen Wiig in the cast. Feig does not bring that up at all but I honestly do not see a sequel produced without Wiig's involvement!
Most of the time, sequels are produced to bring in more money from the fans of the first film. Sometimes, such as in the case of last year's sequel to The Hangover, they don't always build upon the success of the first film. The first one finished it's run in 2009 to a grand total of $277,322,503 whereas the sequel finished it's 2011 run (with an increase in ticket prices, no less) with a smaller total: $254,464,305.
I heard today that there was talk of a sequel to Horrible Bosses and I don't get that. Does Kevin Spacey get out of jail or something in the sequel? Or does Jennifer Aniston do something more extreme? You can't just beat a dead horse over and over for more money. It just does not fucking work. It simply does not. Don't get me wrong--I like the cast and writers involved in the film but unless they have new horribly insane bosses, what else can they do?