Ok here are some possible ways to improve hex (I can add hex support to the races that are missing it).

Rather than make it so you randomly get it at any time during a match (like how it is now). You would instead have a % chance to get it for X time when hit by an enemy. So you then know that it is activated and you have the ability for X time.

I could also keep the other version of Hex and add it as a new ability.