Rylais crystal scepter rework idea

Instead of a passive slow on spell damage, make it a toggle. While toggled on, converts 50% of damage dealt into a slowing effect. Gives it a bit more nuance into how you use it, when you use it, and why you use it. Details like damage to slow conversion ratio, duration of slow, toggle cooldown and so forth are balance levers; 50% isn't set in stone.

What do you think?