There isn't much that's going to happen in core development. The P4 is more or less doomed, as it's simply not designed to handle RC5 and other integer/bit-rotate functions well. As for the Athlon, there has been some talk about it, but I think it's close to being "tapped out" too. If you want a concrete answer though, try dropping by the Dnet
plan files, and emailing Moose about it, he has the final word on these matters.