Mark and host John Montgomery would like to see improvements in 3D and user friendly sharing of encapsulated presets, expressions, & scripts. One area of improvement needs to be in Dynamic Link and the RAM pool, which can get out of control when too many instances of the apps are running. Even the headless instances of Adobe apps running in the background have "giant pulsating brains."
You can find links to more on CS5.5, including Mark's review, on AE Portal.