Karthus Rework Let's actually be a terrifying Lich

So hello everyone was at work today and was thinking of the tank meta we are in right now and how few mages there are that are actually good at facing tanks namely Brand and Vel'Koz and the idea hit me. What if Karthus was reworked as an anti-tank mage think about it. The idea of a lich, at least from its most known D&D roots, is to be a masterful wizard that wished to maximize its potential as a wizard by seeking to further themselves in death and gain immortality through it. To this current Karthus doesn't really capture that idea nor does he really excel at anything. Even in terms of late game mages he falls by the wayside when compared to Xerath, Malz, Vel'Koz etc.

I thought on it all day at work and wanted to share my thoughts with you guys and get your opinion. So onto the kit I have in mind.

Passive: This is the big change does anyone remember the revive spell? I honestly think Karthus was the only one that ever even considered it and even then it was pretty trollish. As it stands now Karthus gets to stay around when he dies and if the enemy is stupid stand next to him and do decent damage....and that's it best case you can get a few cheeky kills worst case you are spending even longer dead while doing nothing.

So here are my thoughts when you think of a Lich one thing should always come to mind and that is his phylactery. This is the item normally a flask/urn that they bind their soul to to live forever. So I was thinking that we should give Karthus this as well. A stacking mechanic where he gathers souls/essence from foes to forge his own phylactery that once filled he can consume a charge (Not sure how many I'd let it stack to yet.) and just like the old revive spell instantly come back at base where his phylactery is stored. Queue cool ass reanimation scene.

Edit: New thought while at work today perhaps make the phylactery upon use pull upon the essence of the others in the form of missing health damage that scales with each subsequent use of the phylactery. Although the charge required to fill each phylactery also increases as the game goes on. Either make it a global thing hitting everyone or have the phylactery actually keep track of whose essence was used to fill it and only sap their life upon use. Gives further incentive for Karthus to combine all his abilities and passive.

Q: Still thinking on this one his Q now is okay but I'm thinking maybe make it more like a magic missile with a possible ammo system like Corki missiles

W: A draining tether that slows and lowers the resistances of a target similar to the aging and other necrotic abilities LIches are known to employ

E: Here's where things change a bit I like the current look of his e but find it too mana intensive while also being lackluster in terms of damage. This is also where his tank hating playstyle can begin to take shape. His e look wise would be similar only it would do damage and then drain essence from foes around him. (I'm thinking a cool withering sort of effect with small tethers showing who is being drained.) devouring health based on current health percentage. Think of it like the draining/chilling auras that Liches are known to emanate in their various base sources.

R: Now his ult which is where I take his old passive and give it new meaning. I'm thinking it can only be used while dead and that he still goes into an incorporeal state and puts up his E quickly draining those around him only with a twist depending on how close you are to him you are slowed and drained even harder with higher base damages and possibly higher Max HP draining threshold. With damage from this rapidly filling his phylactery passive. As this ultimate goes on the E around him expands to encompass a larger area as an area denial and massive sphere of death.

So these are some quick thoughts I would love to hear your guys thoughts on it and if you like it would humbly ask you to upvote so that maybe Riot could see it and who knows could use it someday. I plan on updating and working on this as new ideas appear. I know thinking of appropriate names is a big milestone, but best wishes guys and if you are still reading thank you so much for your time.