Michelle Rodriguez isn't a terrible actress, she can just really only play one character (though she does that character pretty well). If the character she is playing fits that or is written around it, it works. If it's not, it doesn't. That's really all it comes down to.
In this case, it worked, because the character fit her style.
Seplito
Nash, Smelling Like the Vault since 1996
Step FOUR! Get Paid!