Just curious if any one else has noticed longer save times in Platinum as opposed to X3. This may only be an issue on large projects, but I seem to be watching a spinning circle a lot more than usual lately.

Yeah agreed... Autosave is long and a little disruptive... Background autosave would be my #1 on the wish list. Not sure if it is longer on Everett or not but my projects do take a decent amount of time to save.
Also check your project size, there is still a bug with audiosnap that can cause the project file size to double at every save.

Auto save is a background function. It's not supposed to activate until any processing that could be interrupted by it has stopped.