Well that riving knife would be crap even if it were not bent. That open slot will not prevent the crown guard from being ejected if I large chunk of wood hit it hard enough,
I love my Excalibur but the guarding is not its best feature. I junked mine, made a new riving knife out of mild steel, which is OK but not excellent. I've just taken delivery of some gauge plate (Thanks, Bob!) to make another, and I have a couple of different kinds of guard (you've seen them, I think) which is a much better solution than what comes as standard.
Remember that this otherwise excellent saw is not CE rated (at least, mine isn't - maybe things have changed), so you have to live with its deficiencies. It's built like a tank though, so it's worth spending some time and effort dealing with its few shortcomings.
HTH
Steve