"prosecutors are discouraged from pushing through cases with weak evidence"
How dare they?
We should prosecute even if there is no evidence what ever! After all, the prosecutor in the Jill Dando/Barry George case bragged that she had got a conviction with no evidence at all - and they promoted her. Of course, it later turned out that Barry George didn't do it, but what is that compared with getting better statistics
PS: The fact that a woman gets so sh*t-faced that she cannot remember whether she gave consent or not is no excuse for rape.