back in the day if you took electrocute and spammed e from level 1 you'd just run out of mana first while the enemy healed up with 
+ second wind sustain
now you just trust in deathfire touch, cheap shot, presence of mind, and manaflow band from level 1 and spam e. the enemy's hp drains faster so it's easy to take early priority
you just do this shit from level 1
on top of that you hit level 6? the moment you drop your ult it's a deathfire stack party
the damage used to feel lacking when you only had this but now deathfire + cut down as a secondary rune fills that gap
she was already annoying as hell but now she's annoying, has high dps, and is tanky as fuck. what a crazy bitch strong laning, good scaling, great teamfights, and even good at stopping dives. absolute cancer champ
this deathfire rune is actually fucking insane
even if you just land a single target skill it's only slightly weaker than comet but it has no cooldown and unlike comet you can't even dodge it since it's a burn
if you're a mage champ that spams skills or has dot damage the synergy is basically core item level