When Gary and Patricia Nave purchased 16 West 86th Street for $350,000 in 1979, the water was brown and the ceiling was missing in places, a far cry from the mansion it was when a member of the Macy's Straus family purchased it in 1913. The Naves restored it, but perhaps not quite to its former glory: the broker tells Times the now-on-the-market building?10 1BRs and a medical office?"calls out for a person who thinks bigger and better." Looking at the listing photos, we'd have to agree. The brokerbabble points out a potential extra 15,600 square feet of buildable area in a rather halfhearted effort to find a buyer who'll pay the $8.95 million asking price. Will anyone step up?