Why Karthus is not very Unique

Rito mentioned that the reason Karthus was not considered for the mage update was because he has a very unique kit, and that he would be looked at after the item update to see if he still needs help (he does). But is Karthus really that unique? Out of his entire kit, only half can be considered unique or even useful when trying to combo with another ability.

Death Defied "What do we say to Kindred? Not Today!" Here is one of the two unique abilities on the kit. This ability lets Karthus cast spells after Death for a brief few seconds, mana free. Unlike other zombie passives, this one allows you to cast spells. But it only rewards you for dying, which unless you actually do becomes useless if you have a perfect game. But that is a good trade off for how strong the passive is.

Lay Waste "All that potential.WASTED!" This spell is highly unreliable and is not nearly as rewarding. The cooldown and "trigger" moment of the spell is just long enough to be fair but too long for Karthus to actually lane against an opponent with it. This has made laning with Karthus a Farm simulator (No stacking) since any champion with boots or a spamable dash can poke Karthus without taking a single Q damage. But what is even worse is that this skill is not Unique, nor as rewarding as other skills. These champions have an AoE ability that both allows them to farm and harass the enemy easily. The only difference is that they have a longer cooldown so it is allowed to hit enemies more easily. I would be willing to give up some spam for more reliability like other champions.

Wall of Pain "Tis but a Scratch." This ability has been nerfed to near useless and is also not very unique. Sure it makes a really big wall which people can't avoid, but you know who else can make a better wall (No not Trump) Unlike Karthus their wall people cannot pass. Sure Karthus has %MR Shred but when landing Q's are really difficult it almost does not matter. But it also slows, which unfortunately has been nerfed and slows do not do anything against dashes. Hopefully if "grounded becomes a thing this could be added to Karthus' wall to help against the increasing pool of mobility creep.

Defile "I feel so violated" This spell makes a pool of magic damage all around Karthus, sounds unique right? Wrong! These three all have toggle AoE abilities that drain a resource over time, and there are many more that have more utility built in that are either not a toggle ( can blink in fights) or do not have to be centered on themselves ( comes with a slow too)

gets a %health shred which would be nice on Karthus since his Q is hard to land, and he is squishy which means he can't just spam it into fights and not get blown up (then his passive takes over but you could balance it easily to do less with it).

gets health back while doing damage.

these two champions have a similar ability but are allowed to be given more probably because of Karthus' most unique spell of them all.

Requiem* "I AM THE LIGHTBRINGER!"-Karthus This is perhaps his most unique and well known spell. A "press R to win" button. The only problem with it is that it might be deemed too powerful. Karthus is given a weak laning phase and a weak trading kit because of how much reliable damage he can do with his ult. Late game my Ult usually does 1k ap damage. 1k of click and do damage. The only problem is that if you cannot avoid it, you die. If you have any means of avoiding it your chances of living skyrocket. Because of new champions and items Karthus ult can be easily avoided whether it be : ITEMS: YOUR KIT ABILITY: SOMEONE ELSE'S KIT ABILITY: OR A CC THAT STOPS THE CHANNEL:ERROR LIST TOO LARGE.

I get the cc to stop part, but does it have to be so easy to counter against once he cast it? I could name other champions with a similar ability but that are all skill shots or AoE related. So well done Riot there is one unique ability but this should not exclude him from a rework or at least a touch up. Especially with the new items coming out, so please consider him for at least an update to his kit so he doesn't feel useless early game, or God forbid his late game.

tl;dr Passive Braaaains. Okay skill Q Skittles attack not reliable Similar but better skill. W Wall of extreme minor discomfort. Trump would rather have since there wall is useful for stopping people from crossing it. E Blue Jacuzzi generic and does not do much other than damage. Archaic skill that needs to be updated to have utility similar to other champions R "PENTAKILL" maybe. Very unique skill but too easy to avoid with an increasing amount of items and skills as the roster grows.

EDIT: Forgot could dodge it as well and apparently as well. Also added