To the initial question: Overall SL is certainly on a downward trend for me. I haven't really noticed any change in rez times, loading, or anything that would be related to the latest performance improvements. What I have noticed is a marked decline in the ability to successfully teleport, login easily and generally script, build, or interact in the world. My entire group has been noticeing a steady decline in overall performance lately - I wonder if these new enhancements have come with other costs?
In any regard - the overall user experience is much worse for us then it has been. It could be a fluke but it certainly doesn't seem that way - too many are affected. Group communications seem worse then ever and this new inability to TP without crashing is an entirely new thing.
All the performance goals sound great though - I applaud LL for working on this. But I can't attest to an overall improvement - the net change is a negative one - sorry.