As for the new features of Live 8, it's still blowing my mind that a clip has crossfade CURVES but automation and clip envelopes are still lines. Classic WTF.
The reason they are not in L8 (IMO) is that the implementation of curves on automation is much more complex than on a fade. For various reasons.
On a fade the curve is going in, or it is going out and there is a curve-shape for that curve.
On an automation there is much more complexity: up,down,up, really down ...off in fact, up to the top again, wibble about a bit, etc.
Now, the crossfade system is fine and dandy for handling the big brutal single curves of a fade, but imagine a bar packed with a a large amount of such curves, perhaps your wibbling might produce 20 up/down movements in a bar, each with differing rates and curve shapes.
Where are the handles for these? How are they represented? Does the solution interpret old automation well? how do they interact with the 'pen' tool? etc etc...
Fade Curves of course do not have to handle any 'old' legacy automation, as they are completely new.
so that's why they are not in L8, because it's a can of worms - not simply a straight copy and paste of a code block