As a leading man, with or without the padding and makeup, Lawrence is a questionable choice. To date, his box office success has come when he's paired with someone with a bigger name, like Eddie Murphy or Will Smith. He is yet to have a hit going solo, and there's nothing in Big Momma's House to convince me that this will represent a reversal of fortune. Perhaps that will sell a few curiosity tickets. Long, Giamatti, and Howard - are so bland that they often have difficulty standing out from the scenery.
Dumb comedies can be funny, but only if there's an underlying intelligence behind all the stupidity.
There is no evidence of that here. Just because something is supposed to be funny doesn't mean it is funny, and that's a distinction that was lost on the filmmakers. No matter how desperately you want to laugh, this isn't the outlet. The best way to avoid walking out of Big Momma's House is not to enter in the first place.