So Viktor has something of a unique situation. While there are other champions who utilize unique items, such as Rengar, he's the only character "forced" to take his and without the ability to sell it.
I say "forced" because - The item does add a unique dimension to the character, is part of his identity, and does have the unique potential to build his skills in a way that is incomparable to any other character. He's something like Kha'Zix and Rengar combined - An item that allows a one-shot opportunity to "adapt" to your situation, whether that's your lane, enemy team, or even a change in meta.
These are simply a few design ideas. Hopefully they're good on their own - Worse comes to worse they introduce new discussion into a character which is, as of this moment my favorite AP Carry.
[Sorry Morgana and Cass, pewpew lasers and Russian accents are my weakness.]
These augments, rather than modifying a single ability, will alter all four in a unified direction. The purpose of these changes would be for a player to choose a design that best compliments his team. (I understand that's confusing, and I'll expand on it.)
Augment of Denial
Increases Mana Regeneration by 35%
Power Transfer: Enables use on ally. Provides shield and will cause next stun or slow to last 50% duration.
Gravity Field: Projectile skillshots passing through the field are instantly slowed by 28% / 32% / 36% / 40% / 44%
Death Ray: Death Ray will leaves a burning scar in the ground. Enemy units passing over the scar suffer 30% damage and slow.
Chaos Storm: Chaos Storm may be cast on an ally, who it will automatically follow. Every three seconds of sustained exposure will incur a .5s silence effect on enemies.
Purpose: The intention here is to obviously provide a support aspect.
Without the ~124+ AP and 30%+ damage of Augment Death, he is no longer nearly as effective of a carry. Assuming Deathcap, that is a loss of:
~80 damage on Q
~240 damage on E
~280 (max) damage on R
In return he can shield allies, potentially help dodge skillshots, and provide area denial to escaping or advancing enemies.
As another example:
Ability casts incur stacking 10% speed debuff for 1 second.
Power Transfer: Upon return, Viktor receives 5/10/15/20/25% movement increase for 1 second
Gravity Field: Opponents stunned by field receive 10% additional damage
Death Ray: Renamed "Thermal Lance". Delayed skillshot - charges, then instantly pierces all enemies in line. This ability has 5/7.5/10/12.5/15% MPen.
Chaos Storm: Every two seconds, Chaos Storm gains one charge. If an enemy unit is selected and within range of the storm, a charge may be expended as an additional hit at AoE damage.
What is the purpose of this? First, lowering the AP gain. By the time you buy Augment Death, it would usually be a 60-70 AP boost plus 30% damage - which allowed a Viktor who got an early lead to dominate. [Which is incredibly fun, but I digress].Additionally, with S3, I feel MPen has received a boost, so going back to the old AP standard would be silly, particularly with the new additions.
These new additions promote skill use over the usual burst meta.
This augment significantly reduces Viktor's ability to escape fights (No more escape-harass lasers, and blowing everything you have on a gank reduces speed) at the cost of a significant damage boost when utilized correctly.
Power transfer late game allows you to overcome the movement drain unless you drop everything at once, at which point you're committed.
Gravity Field offers a pleasant trade-off for the lack of mobility.
Thermal Lance capitalizes on the new MPen meta, still offers unsurpassed range and boosts damage, at the cost of easy harassment and removing the unpredictable nature of the laser.
Chaos Storm is a simple damage boost. Use Gravity Well to get the most of it - But remember that with the new debuff, a good Viktor player must know when and when not to commit.