I suggest you read the section on Rylai before disagreeing with it.
Gunblade IS your highest damage item. By far. The nerfs barely hurt her. Damage-wise, you lose 20 AD and 5 AP. It's annoying, but not game-breaking at all.

What you are proposing is a tanky dps Katarina. Which would be fine, if actual tanky dps mages like Vladimir or Ryze didn't do that job several times better. Playing her as an assassin, I like investing in her maximum damage output item. I KNOW that you're sacrificing 500 health for a measly 20% spellvamp and 15% lifesteal, and it requires a full 3 waves to actually regain 500 health from said spellvamp. However, I've come at a level of play where my ennemies are often capable of not ******edly suiciding every single wave, and thus the spellvamp and lifesteal outweigh the 500 health.

On the WoTA: You're suggesting replacing your highest damage single-target item by 500 bonus health and a lot less damage for an added 1980 gold? I did the math on it, you can check up on it. Here's the difference in single target burst damage: (2 values are the extremes: 0 daggers on ult - 10 daggers on ult. This is purely the damage due to scaling and the GB active, as base damage is independant of build.)
Gunblade: 409-784
Rylai + WoTA: 176-576
Difference: 233-208 more single-target damage in favor of Gunblade.

So your claim is that 233-208 extra burst damage on an assassin, paired with 1980 gold can never outweigh 500 health? You realize that I can buy a Giant's Belt AND a Doran's Blade with the extra money, have EVERYTHING useful you have, plus over 233 extra burst damage (counting the D blade's AD), 10 extra health, 18% extra lifesteal and still beat your build's gold-efficiëncy by 395 gold?

I disagree with the rylias issue, part of the reason u purchase it isn't for the slow itself but also the survivability the 500 from it alone is easily an extra 30% hp to katarina which allows you to much easier gank and exchanges harass. Not to mention gunblade is a terribly inefficient item for katarina after the nerfs and the spell vamp by itself will never be enough to make up for the hp not to mention for over 1k cheaper WOA gives u the same spell vamp and ap.

I start off with boots + 3 pots because I feel it's generally the best starting combination in lane. I basically rush Hextech Gunblade, as I consider it Katarina's main item, and get Sorcerer's Shoes in between. I generally start with the Hextech Revolver component of the gunblade, even though the AD component is actually more cost-efficiënt damage-wise, because the spellvamp gives you invaluable lane sustain.

After finishing my main item, all other items are pretty much situational. I usually go directly for a Deathcap + Void Staff if I'm either fed or if my team is doing REALLY badly. In most non-snowball games however I prefer taking a more tanky-damage build including Zhonya's Hourglass and Abyssal Scepter.

I consider Rylai's Crystal Scepter a very situational item and rarely ever get it. I really do like Fort pots or a Doran's Blade early.

I thought I mentioned all that in ghe guide? Maybre your page glitched?

WTF IS YOUR BUILD

nice guide :)

Great guide, Katarina is my favorite.

Thank you for your feedback, it's a very good suggestion. Consider it done!

Very well done ^^

I love Kat, she is my main and I've got to say that this is a fantastic guide. I've read most Katarina guide and this is one of my favorites. Very well done ^^

Though a common problem with Kat players are usually late game if you didn't snowball that game. If I may suggest to make this guide even better a recovery section for Kat games gone wrong. What they can do or try to if they have a bad game. (everyone does from time to time)

That's all I've got to say but all in all extremely well done guide.

You make a very good arguement there.

This is because her teamfight potential is very high. Now keep in mind when I say "good lategame potential" I do mean she has good lategame potential compared to other assassins. Falling off lategame is a common assassin trait, and like her peers Katarina shines midgame. Obviously other mage types inherently are more powerful and versitile lategame.

However, Katarina's inherent way of snowballing in teamfights due to proccing Voracity gives her the ability to still destroy entire teams lategame, given they either have a big flaw in their teamcomp or they made a positioning mistake. This requires good timing and positioning on Katarina's part.

The thing about Kat is her burst potential is larger than that of most assassins, and it gets delivered faster. (Imagine making Leblanc AoE and buffing her damage.) The price she pays is complete and utter uselessness if she fails to get a kill. So good timing and positioning still make her a real threat lategame.
Combine that with her exellent baron fights (fights in the jungle in general), due to her ultimate not reveiling her. I almost always get off a full ultimate on multiple ennemies in the jungle, and the only times this hasn't worked is when I was apparently standing on top of an ennemy ward.

Now getting focussed down IS an issue, but that's why I suggested not rushing Deathcap after Gblade unless you're fed. Zhonya's and Abyssal give you a way out of the ennemies focus you down. You're also allowed to get a purely defensive item if you're in trouble. Your itemization options are pretty huge and the optimal choice varies hugely from game to game. This is the main reason the "suggested build" I posted only shows Kat's core starting item sequence.

Also keep in mind that you have the option of killing ennemies off more often than you might think. You just need to time it right (or perfectly), and be fast about it. Katarina's main speed limitations tend to come from "how fast I can press buttons in the right order" rather than cooldowns.