Pre-Katrina, we stayed at that Sheraton in late December and had absolutely outstanding service. It used to be a great time to visit New Orleans because it was the slowest time of the year for tourism, so hotel rates were super low and everything was uncrowded. I remember one year we were told only 20 rooms were occupied at the Sheraton during the week between Xmas and New Year's Eve. The staff really hustled for the few guests staying there. The bar was always closed, though, and the restaurant had limited hours. I guess the hotel management just couldn't justify opening them with so few guests.
Unfortunately post-Katrina the service at virtually all hotels and restaurants in New Orleans tends to suck badly. They can't get anyone (at least anyone competent) to do low-level jobs -- in particular valet parking. When NOLA Burger Kings are paying a $6000 signing bonus for flipping burgers, why would anyone want to be a parking attendant?
We had similar valet woes at another hotel in the CBD earlier this year. It's a fact of life there. Stinks, but what can anyone do?
No idea what the homeless guy was all about. He was probably a staffer's family member or something. That's the Big Easy for you. Things have always been a bit "loose" in that city and they're even looser now. (All my husband's relatives live there, so I know whereof I speak!)