I think in this case, it is a case of who ought to stay, rather than who should leave.
Doing a quick analysis
In Alphabetical order
Nush
Before she came in she escaped from a religious cult. As I have explained before, some of her "game plan" may mearly be residuals from the programming these cults do. Ever since she went in, it was reported that the cult leader had been phoning the production team every day to say that any prize money should go to his religious group. Nush needs to be protected from this group for as long as possible, to assist deprogramming. Ergo Nush needs to stay.
Steph
The only chance there is for romance on BB4, with Cameron. Ergo Steph needs to be kept in.
Also if there is something, then Cameron fans should keep her in for tactical reasons as she will not nominate Cameron.
Tania
Sorry the god's demand a sacrifice
I will not be voting for Tania to leave, but for Nush and Steph to stay. Tania would merely get evicted as a side effect