Maybe it's not worth worrying about mobility and charging, etc. Want just to drop it?
Vulnerable wings could work.
Ok, let's go with aerial dodge and forget the vulnerable wings. Sure.
Either of you remember what we called the rend like version? The one that gives auto bite damage on two successful attacks?
You've got some kind of broken link there; it thinks I want to edit your working draft. Anyway, I think it's ok up to flavor. Fluff it up!
When in doubt, guess "gnaw".
Gnaw (Ex): An agriotherium that hits with both claw attacks may make an immediate free bite attack. Additionally, it deals automatic bite damage every round it maintains a grapple.
Looks good. Do you have description and flavor text, too?