A Review of a (poor) Karthus guide

A while back, I was on the League of Legends forum. I noticed a post asking people to look at this guy's Karthus guide. I gave it a look and replied. Here is the guide: http://www.mobafire.com/league-of-legends/build/a-million-ways-to-be-cruel-225866. Here is my response:

SUMMONER SPELLS: 

Honestly, those are based off of personal preference. Personally, I prefer flash and ignite/exhaust (ignite for champs that heal ie: fiddle/swain). Exhaust has great synergy with the wall, landing Qs, and keeping them in the E radius.

RUNES:

 I have never used Spell Vamp quints, so I am not going to comment on that part because I know some people swear by them. What I do know about spell vamp however is that it is more valuable early game and starts to show diminishing returns the longer the game goes.

I have a big problem with your CDR yellows. Karthus has an extremely short cool-down on Q, an average one on W, virtually no CD on e, and a VERY long CD on his ult. By picking CDR yellows, you are only specing into his ultimate, essentially. Health, Armor, and Mana Regen/5per lvl are all better choices.

BUILD: 

Should be Boots/3 health pots to start. The mana pot is POINTLESS because of the mana sustain from E. Tear is a good item for Karthus. Revolver is also a good item for him, but at this point you are committed to staying in your lane and farming to high hell. You won't be as beefy as a Karthus who chose to go the boots>RoA route (a route that is good for early teamfights) and you won't be doing as much damage as a Karthus who went boots>double doran>deathcap (a route that is great for lane dominance, if you managed to get ahead early).

You make the mistake of recommending the purchase of AA Staff and WoTA in early/mid game. AA Staff is not worth the money early/mid game and neither is WoTA (unless you have chosen to run a double WoTA comp).

Also, I would prioritize Zhonya's over Deathcap if you are playing suicide bomber Karthus.

Furthermore, you do not have a single defensive item in the build. Abyssal and GA are both great items on Karthus.

ABILITY SEQUENCE: 

R>Q>E>W (I typically get a 2nd point in W at lvl 10) Fix your guide for this change.

MASTERY PAGE:

Yikes. 9-0-21 is NOT GOOD on Karthus. You need to be dealing damage to high hell. 21-0-9 or 21-9-0 would both be better options for you.

Like I said earlier, Karthus doesn't scale off of CDR well. I don't think anybody uses Good Hands, honestly. Awareness is pointless because you are in a solo lane. At best, you're going to beat the other mid champion to lvl 6 and get a kill faster than him. Then what? Nothing.

MATCH-UPS:
Impossible matchups: I agree with all of them except Vlad. Vlad shouldn't really be a problem.
Yellow range: Ahri should be moved up, Veigar should be moved up.
Easy: Annie should be yellow (avoid harass and her combo is a win for Karthus, but he will lose if he tries to fight her), Ryze has to go to impossible (See Annie... but Ryze is scarier), Swain to yellow.

SUMMONER SPELL SECTION:
Ghost is odd to me. Anything ghost can do, flash can do better (unless you are olaf or vlad).
Heal is a preference, not mine though. I don't recommend it though because most AP mids run ignite. Ignite > Heal.

TP is great for ganks.

You recommend Revive? NO! I repeat: NO!

FINAL THOUGHTS:
You're missing the point of Karthus. Spell vamp is fine and dandy in lane for farming/sustain but once you get out of lane where the teamfights happen in seconds, you will not be able to sustain the damage being done to you for the amount of damage you are putting out (because your build/mastery combo is bad).