Cast on Gems Rebalance Suggestions

1: revert the nerf but add a cooldown so it's not spammable
or
2: Reduce by x2 the number of white mobs you need to trigger it (around 5-6)

Do not hesite to share your suggestions here.

i'm a lvl 60 full ice sorceress and i sometimes struggle to clear pack of white mobs since the nerf but have no problem with bosses. I'm at act 6 right now and i don't know if my build will be viable for endgame.

Edit: after tweaking a bit the build i finally reached maps but i've hit a wall of bricks just after that. i will probably do a new character while i figure out how to make the build viable for EG, i want to try lighting sorc and merc now