A herpderp I think ad caster vayne player here?

Garbage. Not voting because I have a kat guide myself, but still, complete garbage.

On-hit Kat? Da fack u smokin bruh?

Just as a reply, even Malady isn't as important to the build (in my opinion) as Nashor's Tooth is. It still has an average amount of AP, isn't too expensive, and gives you 'some' CDR for between kills so you can spam your abilities for sustain from the Gunblade that most people build anyway, which also fits in with getting more from your lifesteal with a higher attack speed. These last few games I've been playing have shown me that just rushing Nashor's first and continuing a normal build from there makes Katarina's early game much more stable due to increased early dps.

All good, sorry for the misunderstanding. The way you phrased that made it sound like you're accusing everyone else of having autism, which is a common thing immature people tend to do on the internet.

Just focusing on the item build, I can tell you why this is not considered as something that works: people do not sit back and do nothing when you autoattack them. Katarina is a squishy champion and you're giving up her insane burst potential for some extra damage on autoattacks (some quick math shows me that compared to an AP build that costs the same gold as your guide's recommended build, you need to autoattack an enemy ~19 times to make up for the damage difference due to lack of AP). If the enemies let you autoattack them to death instead of just turning around and killing you, you're probably playing against bots or unskilled players.

There's another reason why people don't build cooldown reduction on Katarina: Voracity. If you get an assist in a teamfight, all your basic skills reset and your ultimate has 15 seconds shaved off its cooldown. If your passive triggers, it doesn't matter how much CDR you have; even at 0% CDR you get full resets on Q, W, and E, so you get to use them again. Since CDR items do not tend to have lots of AP with the notable exception of Deathfire Grasp, it's generally a superior choice to build full AP items.

If you can't laugh at yourself, you can only cry. I am not in fact insulting anybody as I do have autism so please do not start with the holier-than-thou attitude, and I have graciously accepted your constructive criticism while offering a retort to your cooldown comment. Also, my ignorance to the definition of On Hit was a fact and I was apologizing to someone else for arguing over what I thought it was.

FYI, it's generally a poor idea to immediately begin insulting people using ancient unfunny memes upon receiving negative feedback.

Having looked up the definition of On Hit, I have retitled my guide accordingly. However, situationally you can also build Deathfire Grasp rather than Rabadon's which leads to the full 40% CDR, which makes Shunpo about 5 seconds for cooldown. That's not short enough for you? Also forgive my ignorance, I can't hold all these autisms.

That "low cooldown" is longer than most teamfights. Plus, Katarina is melee. On-hit builds with melee champions that don't have a skill which applies on-hit effects is generally a dumb idea. (Additionally, this is not actually an on-hit build.)

So a low cooldown gap closer with MR shredding basic attacks isn't on hit?

This isn't even an on-hit build. :S

Not to mention that nothing in Katarina's skills lets her really utilise any on-hit abilities effectively.