Nekros, even though being an old Warframe from back in update 10, has kept a good degree of relevance through updates. However, I feel that he needs a bit of polishing on his kit. These are my suggestions for a kit update on the Warframe Nekros in order to bring him up to today's standards.
1- A New passive ability.
Right now, the current ability is barely noticeable and completely obscured by popular mod choices. To make this aspect of Nekros fit better on his kit, here is my suggestion:
New Passive Ability: Doom
Every few seconds, a random nearby enemy is Doomed do death, gaining a unique mark hovering above them. Doomed enemies will be revealed in the radar to all allies and take 100% extra damage. Only 1 enemy can be Doomed at a time and the ability will have a cooldown after the Doomed enemy is killed or Nekros moves too far away from them. Boss enemies cannot be Doomed.
This will keep in line with Nekro's theme of a death bringer and provide a degree of team support. This style of effect will also synergize with the following suggestions for Nekro's kit.
2- Additional effect to Nekro's first ability "Soul Punch"
Being a "bullet type" ability, Soul Punch should be kept as simple as possible. The current effect does little more than just scatter enemies around, so something more substantial should be added to it. For such, this is my suggestion:
Add an effect to instantly kill enemies that are at 50% health or lower. If the killed enemy was Doomed, the mark will immediately refresh cooldown and Doom another random enemy.
Currently, this ability sees little to no use in most situations, even with its Augment Mod applied. This will incentivise players to use the ability not only for a killing blow but also to effectively use the new passive suggested.
3- Raise Armor Reduction of Nekro's second ability "Terrify"
The current 20% reduction is getting quickly outpaced by other Warframe's ability who can easily remove more, if not all, and with less effort. This is without mentioning the "fear" effect making enemies run around aimlessly and harder to hit properly at times. As a change, this is my suggestion:
Increase base Armor Reduction to 50% and have Doomed enemies additionally be Disarmed.
This increase will compensate for the moving targets and not overtake other abilities more dedicated to Armor Shredding while also including synergy with the new passive suggested.
4- Nekro's third ability "Desecrate" is ok as is
Nekro's 3rd ability Desecrate is fine as is. Just add a little effect to synergize with the new suggested passive.
If a previously Doomed enemy is Desecrated, they will be guaranteed to drop a Health orb and an Energy orb.
5- Change completely the mechanics of Nekro's fourth ability "Shadows of the Dead"
Currently, Shadows of the Dead is used very seldom, only for either minions to distract the enemy or damage reduction via its Augment Mod. And even in those cases, the fact that it brings exact copies of enemies can sometimes work against the player. Some enemies like Ancient Infested Healers and Grineer Bombards are preferred targets for Shadows due to their capabilities directly aiding the player by, respectively, healing allies and disrupting enemies at range. However, there are many enemies that either serve no purpose other than distractions or outright encumber the players, such as Nullifiers whose Fields actually block your own attacks or Ancient Infested Disruptors whose protective aura serves no purpose against anything that's not a Warframe. To solve these problems, the ability should instead use a standardized selection of possible Shadow Minions, regardless of who the player kills, and work on a resource based system of "souls" to be gained via killing enemies, thus also allowing the player to adequately keep track of the number of minions they have at their disposal to summon. Elaborating on this suggestion further:
Shadows of the Dead
Whenever Nekros kills an enemy, they will harvest their Soul, displayed on a counter in the lower right corner of the HUD where several other ability counters are used. Killing light or medium enemy units will yield Lesser Souls while killing heavy or Eximus units will yield Greater Souls. Activating the ability will spend these souls (Minimum of 3 Greater Souls [Less if fewer are available] while remaining slots use Lesser Souls) to summon Shadows. The type of Soul determines what type of Shadow gets summoned:
Lesser Souls - Will randomly summon either Ranged Lesser Shadow or Melee Lesser Shadow which work as light units with Ranged or Melee attacks respectively
Greater Souls - Will randomly summon from a list of Eximus-like Shadows:
Healer Shadow: Essentially an Ancient Infested Healer. Since that type of enemy is one of the most desirable for allied use, one of the Greater shadows should use it, giving access to that type of support in any type of mission.
Aggressive Shadow: Heavy unit that mainly attacks with strong ranged attacks, but occasionally will strike nearby enemies with melee. Will perform the traditional "Ground Pound" move most heavy Grineer units use.
Quick Shadow: A swift melee shadow that moves in fast, performs evasive dodges and can use the traditional grappling hook attack to pull enemies towards themselves for speedy melee attacks.
Limiting the types of units summoned as Shadows will make the ability more consistent and using the Lesser and Greater soul system will help synthesize the more efficient enemy abilities while removing the risk of accidentally summoning something that does more harm than good.
The visual aspect of the Shadows themselves should also be limited to a few faction-specific models (if possible, according to the factions present during the mission) for aesthetic purposes. The models then should use a different set of animations to better distinguish them from existing enemies (I suggest the zombie-like animations of the enemies that appear in the "Chains of Harrow" quest). This will help players tell friend from foe with just a quick glance.
Additionally, to synergize with the new suggested passive, killing a Doomed enemy will always yield a Greater soul and the soul will always be harvested even if it wasn't Nekros dealing the killing blow.
Overall, this is a simple suggestion to update an old Warframe. He may not exactly need it, but it's always good to update Warframes before they start to become obsolete rather than only acting after the fact.
I won't mind if Digital Extremes uses these suggestions as they are or just as pointers for their own ideas. These are just my thoughts and they're worth what they're worth.
Thank you for your time and have a good one.