Cool aikido, iaido, and jodo demo, including the multiple opponents aikido randori that I was talking about with Rick last night. Notice in the randori that the tori does not engage in a fight with every single opponnent. In fact, he doesn't really engage any of them. He evades and brushes them off, moving on the the next attacker. Most of the attackers blend well with tori's redirection and brushoffs, ending up in simple forward rolls, but a time or two you can see an uke that hangs on an instant too long, applies force the wrong way at the wrong time, or is slightly out-of-synch with tori, and that uke eats a lot more energy in a bigger fall.
In situations like this you can see that skillful blending is a part of uke's role too - and I don't mean jumping for tori. I mean really attacking, then responding by blending intelligently to remain viable. Ukemi is a kind of intelligent blending. The falling is a natural extension of the act of blending with the relationship between tori and uke.