We have stayed at Napili Kai (just south of Kapalua toward Lahaina) over the Christmas holidays for the last ten years. Yes there is more rain and wind then down Wailea way but it really isn't that much more. The other factors far outweigh the slightly worse weather. To our mind the golf, restaraunts, shopping, and views are much better. Also the bay is very sheltered so it should be fine for a 7 year old. In defense of Wailea, drive times around Kihei are much better now with the improvements to the bypass.

Either way I think you will be happy.

David