Such a move would only hurt his campaign. Hillary had never held elected office up until that point, so it would be an obvious case of nepotism to the voting public. There would probably be a convention revolt because ultimately the VP pick is up to the convention, and if somehow Hillary survives that, she's going to be butchered in the general and a hindrance to the campaign. In addition, there is the added complication of both having residence in Arkansas, meaning Arkansas electors could not vote for both.
Assuming she is elected, somehow, serving as vice president gives her a platform for an earlier run. If the Lewinsky Scandal still happens and the impeachment process begins, the press would run wild with the fact that impeaching Bill would lead to the woman he cheated on becoming president. If Hillary is power-hungry and a lot more ticked off than OTL, she may just pull some strings to get impeachment passed in the Senate. So we get 42nd President Clinton followed by 43rd President Clinton (though I assume she'll be going by Rodham in this case).