Getting it cleaned up and in good mechanical order will help your sale, but I don't like the idea of paint on the deck or in the pool. It will fail in a fairly short time compared to proper resurfacing/replastering and may make future repairs more costly. If you don't want the cash outlay for these expensive repairs (very understandable), I cannot say if a coat of paint would help your pending sale compared to leaving as-is and pricing repairs into the contract. Personally, I would see it as putting lipstick on a pig and make me worry about other hidden problems, even though your intentions are good. Maybe a real estate pro familiar with the market can help with the cost/payback decision.