The animation editor leaves much to be desired, but I've yet to use it for anything but 1 or 2 second long animations that are logically separate, so I haven't really experienced much pain. I've used up to two animation players at once for when I wanted a player's body to act independently from the player's legs, but I imagine I could probably blend two animations together somehow and I just don't know about this feature.
I've never run into the problem with needing to cut a single animation up into multiple animations, I always create a new animation when I know I'll want the animation to be separate from the others.
