What will be the new killer tool in after effects?
#1 new feature: Render Faster Button!
#2 new feature: Steampunk control surface! Real world cranks, dials and knobs! Fine Victorian gingerbread wood inlays. The sweet smell of burning coal.
But seriously, if you've been keeping track of when Adobe releases software, chances any new features would have to have been locked down by now so they can program it in and test it thoroughly.
So really, what would you like to see in CS8? But you can't answer that until CS7 comes out!
Here's an article that I just posted about the top feature requests for After Effects made in 2012:
That should give you an idea of what others have ben requesting. Since we try to satisfy our users as much as possible, this can give a hint about what's coming.
There is basic Ripple Insert Edit functionality. See this page.
Again, adding requests here does no good. Please submit feature requests using the link I gave before. That way, they will be recorded and tallied.