[Wася]

I think, it's a little bit strange to compare ICE with C4D Xpresso, because nodal way of "scripting" exists in Houdini for ages, and is not some kind of add-on, but a core feature.
However, the decision trees approach itself was invented neither in Omnibus, nor in Maxon.
Futhermore, the nodal approach already implemented in Softimage Crosswalk. So ICE is just a logical step. Smart one.

[updated] Silly. Thought about Behavior, wrote "crosswalk". Behavior, of course.