Just because you can sell your home when it requires repairs doesn’t mean that you will get a fair price for it. Some buyers will buy the home and plan on making the repairs themselves. Others don't want to mess with the hassle of making repairs. This makes the pool of potential buyers smaller compared to a home in good condition. This will be reflected in the price of the home.
Once the Realtor knows the repairs will have to be made by the people who end up buying the house, they will prepare the short sale lender and all the other parties for the lower price. If your home needs repairs, then don’t think that this will cause your lender to deny any short sale offer. Above everything else, the bank only cares about receiving a fair market value when the home sells. They know that they must factor any necessary repairs to determine what is a fair market value.