[Trexmaster]

The only thing keeping Void Refraction in check is how long it takes to setup that many void gates to cause it to be lethal, and the fact they all have to be owned by the same person to really make it work. Though with how Black Bolt currently functions it's often not that hard to buy enough time given the RNG throws your opponent far enough. Its strength lies in the sustained burst damage you can deal should you have an armada of void gates lined up and an appropriate projectile to multiply for insta-kills (fleeing spectres currently being one of the major offenders due to how many projectiles it spawns at full damage).

Black Bolt could definitely afford to have a cooldown and as others have said I'm pretty sure Fray was supposed to have been changed to not get refracted.

As for Void Refraction, the only real offenders are multi-projectile skills getting further multiplied. You'd need multiple casts of most single projectile skills to benefit otherwise aside from outliers like Eclair Lacroix, and if the damage was further nerfed for getting multiplied, it'd almost never be worth it to setup unless each projectile carries an effect worth multiplying (Gentle Torrent, Needle, etc). So I'd say preventing Fleeing Spectres from being refracted would be a good start, or removing the ability to multiply projectiles from the same skill more than once per portal (as mentioned in above posts).