I like Ashleigh as a strong housemate, Steven has an unintentional comedic element to him, Pav could develop into an interesting housemate given a little public cheering support so for me I wouldn't miss Zoe as much if she went.
Don't get me wrong Zoe does seem like a nice decent person but I doubt we will get to see her ever let her guard down and relax. She looks as though she is performing all the time because she thinks she has to.