I would add one thing, and it is not a quibble.
I agree.

I like to focus on
clarity more than surprise. We can only deal with so much information at a time. Effective counterpoint means that we have to hear two different lines at the same time, as well as the interaction between the two.
So you'll typically do things like make one part complex where the other is simple, so you only have to focus on one line at a time. Because hearing more than one thing at a time requires
work, and work is
hard. Clear writing keeps you focused on what one melody is doing, while remaining aware of how the others are contributing. It's like listening to a jazz solo being traded back and forth - the other players step into the background and let one player shine, but keep playing their supporting parts.
For me, the beauty of counterpoint is that the independent lines become intertwined and interdependent. They can create and resolve tensions which weren't there in the single melody line; they create harmony; they rhythmically collide and contrast.
As you point out in the
Jesu piece, without the other part to complete the harmony, you won't
hear the dissonance. You need all the parts for the whole to make sense.
I'll also agree that the most important part of surprise is expectation, because surprise
is thwarting expectations.
And I'll agree that good music is able to use the element of surprise to create interest and beauty.
However, I'll still disagree that counterpoint
depends on surprise. I can write terribly boring counterpoint with nary a expectation unfulfilled. It's still counterpoint, even if it causes you to fall stone asleep.
But it won't be
good music.
