"Paying almost 20 per sq. ft. more than the next comparable" is a decision that you made because you love the home and at the time the offer was written you felt that price was not an issue despite the fact that you will have to retain ownership of this property for a potentially long time waiting for the market to 'catch up'.
I believe that rather than making a messy list of things the Sellers have not done and potentially souring the deal, it may be in your best interest to reduce the price in lieu of those items and perhaps in so doing providing the comparables may encourage them to agree to a reduction in price.
In this case, working with a Buyer's agent could potentially have saved you from paying too much for a home.
Circumstances such as these can cause sellers to become very nervous and less cooperative. As my customer, my suggestion from the very beginning would have been to build any "condition concerns" into your offer price and leave the rest of the contract clean. Special addendums have the potential for becoming BIG problems.
You are purchasing this home now. Although your concern for future repairs is a valid one, it is doubtful anyone is going to want to compensate you for improvements needed five years from now. It is plain unreasonable.