We learned a lot of information about Mists of Pandaria at BlizzCon 2011. The early talent trees were released, and so we have a rough idea of what we'll see at level 90. We don't know exactly what abilities we'll receive as part of choosing a talent specialization, but it's assumed that we'll see most of our former talents returning.
While we do have some information, we're still missing pieces of the puzzle. It's likely that we'll receive new abilities in Mists of Pandaria in addition to the talent system revamp. Any predictions about what might happen are purely speculation, but there's no harm in talking about what we'd like to see. I have a list of abilities and ideas that I think fit with the rogue theme, and I'm hoping that I might see one of them implemented in Mists of Pandaria.