How about sorcery keystone with missing HP dmg?

I dont remember even single mage with missing HP dmg. Veigars ult gets increase in dmg depending on targets missing HP but thats not actually missing HP dmg. Its % increase for his own flat dmg. Tanks/fighters have it Adcs have it Assassins have it Mages have max hp dmg... Which is also available to every other class. Some have current hp dmg which is also not unique to them.

There is a lot of other keystones that will work only with basic attacks. Why not give mages something that works only with ability dmg? And also something that they completely lack in their kits.

Mb some kind of dot or something that requires you to apply several stacks before it can take effect? Or mb even instant burst. I know burst belongs to domination but ffs phase rush does not manipulate resources or empower abilities as well. Most runes there have nothing to do with resources or ability empowering. Something like presence of mind from precision by all means should belong to sorcery. Single ability empowering keystone in ability empowering tree is fucking Aery :D Comet is dumb shit only semi good for poking. (semi cuz there is even no guarantee that it will hit) Its like Riot made all the runes and just had completely no idea what should they give to sorcery. "Well mages kinda poking so lets slap something like piece of shit flying in your face after you get hit with ability". Even sound resembles something just SLAPPING at you. Laziest thing even. So that description is a complete scam :D

For example - sustain your own dot on target for several seconds and any of your abilities will deal missing hp dmg for several seconds after that.

Or you gonna say that mages have that works good with dots so they should basically fuck off and not even think about keystone that wont be useless for dots?

Yea you can use aery for DoTs for example but its like using half of its power. It has two components so if you dont have shields its half wasted on you.

Surely It will provide additional build paths or some other interesting options.