Newsflash: Selling home, buyers want steep discount for visible items?

We are currently under contract to sell our house. Buyers offered asking. During inspection some things were pointed out and we are taking care of most of them (like confirming our water heater isn’t original, having our insurance double check roof for hail damage etc.) But they want us to replace the deck. The deck is not original to the home and we agree it could be updated. Which was why we priced the home accordingly. We could have spent $20k+ to build a new one and ask for $660k – instead we listed for $629k. The deck was something they walked on and viewed and (one would assume) consider in their offer. Suggestions? Tell them to forget it? Split cost? We really want asking and it is MORE than fair/maybe even slightly below market because we are motivated. Should we leave this to our broker and be willing to lose the deal?