I can't see Brock vs. Rock - already been done at Summerslam 2002. Although, the WWE have a habit of rematches aka HHH vs. Taker. I wouldn't mind Austin vs. Lesnar as that's not been done before. Not too sure either on Rock vs. Taker either, no real reason for them to be tussling.
Not sure whether the announcing a year before is worth it. It was done for Rock vs. Cena and some might say, the feud's only picked up over the last month or so. A year before should only be done if it's a major match aka Rock vs. Cena.