Ive just had a thought about katarina, after tossing the thought around in my head for a few, i have come upon this conclusion.
Kat is a hero that has one of the lowest cd gap closers in the game, gets a high % damage reduction skill, and scales JUST AS WELL with ad as she does as ap, contrary to popular belief
Combined AP ratio of Q E and R: 1.35
Combined AD ratio of Q and R: 1.3
Most of the bulk of her ratio comes from shunpo coming in at a .75 ap ratio, thats quite high for a low cooldown skill, but think about this. High ratios and low bases (240 is quite low for a nuke) means you have to build a lot of ap for it to be effective, lots of ap means not much tankiness, and shunpo puts you in MELEE RANGE of the enemy (oftentimes its even worse than melee range, its behind them in melee range). So to take advantage of the ap ratio you have to build alot of ap, but to survive the ordeal you have to be tanky. No, 35% damage reduction wont save a 1500 hp kat with 50 mr and armor that just shunpoed into 5 people.
Kat gets focused extremely hard in teamfights, sometimes before she can even ulti or a split second after. Since she has to build a lot of ap to take advantage of her ratios, she often gets blown up in teamfights against decent players. This was semi remedied by hextech gunblade, but with the nerf, it is not as effective.
If we build a tanky dps route however, kats problems seem to solve themselves.
Tanky DPS actually WANT and NEED that gap closer. They can survive it easily, and if people focus them, thats good for the team. This would allow kat to serve as an insidiously hard to kite anti carry that can blink onto an ashe or caitlyn every 4 seconds, even less if she lands an assist or a kill. You dont need cc to be a beast anti carry. Proof? Olaf.
This would also help kats ult alot. This is because for one, kats ult scales exactly the same with AD and AP (.25 vs .5, and ad costs twice as much as ap on average) and with this route, people would be WASTING cc and damage on her, that could have been used on that ashe, or brand, or any other really squishy carry. They cant ignore it either, kats ult still does a ****ton of damage even if built tanky dps.
As a solotop kat would have incredible poke, akin to gangplank, an escape on a low cooldown, and of course she is manaless, thats always a plus.
Build something like
Wriggles (Reason you take it on every tanky dps, gives great sustain, great defense against the enemy top, and free wards.)
Wits end (take advantage of that free 25 damage you get from W)
Randuins (godly on a hero like kat that can jump into a fight and apply it to everyone)
Atmogs (make her super tanky and her ult and Q do a bunch more damage)
Banshees Viel(Make enemy team waste TWO spells on a tanky hero instead of one)
Frozen Heart(same reason as randuins)
Bloodthirster(if your tanky enough to stand focus buy this and **** on them)
Trinity (3.5 second CD shunpo mixed with trinity procs while being super tanky... now thats scary. The slow just makes her an even better anti carry.)
An average build might
These are just ideas for items obv you wouldnt buy warmogs randuins frozen heart all in one game then youd just be a tank kat...
Please give ideas insight and criticisms. I want to know what you guys think of this Ill be trying it out tonight.
TL;DR: Kats kinda bad right now with the hextech nerfs and all, and it seems going the tanky dps top route turns her into an anti carry machine and punishes people for focusing her. Her laning phase top is good with no mana to worry about and poke superior to even gangplank.