I've been summoned by my name and as a chroma enjoyer (I have 25.8% chroma usage rate).
As a person whose been putting on so many band-aids on Chroma since 2017 to make him viable in high-end content, I've grown to like the weapon master aspect of Chroma. I agree that there lacks a fundamental synergy between his build (maybe I'll post a cope rework concept as a separate post) but there is some stuff I still like about his kit today. I'll highlight what I think about each of your points:
Passive: For a frame that lacks movement abilities, Chroma's passive is really comfy.
Having an extra bullet jump provides quicker horizontal movement as opposed to Kahl's jetpack. Also, I feel like this is less of a passive and more of an ability/augment if this is implemented. Warframe passives should be small stat changes or descriptions of how abilities complement each other (like Gauss).
Spectral scream: Yeah, this one is a little bit of a stinker, I don't think the idea of a dragon breath attack (even with chaining) would be top-tier in any aspect today, especially with weapons like Ignis Wraith and Kuva Nukor doing a way better job (and having mod slots.)
Elemental ward: Even in all my years of playing Chroma, I have never actually touched toxin or electric elemental ward. Maybe in simulacrum but never brought out to any real missions. Fire is very comfy in high-end content if you use combat discipline since most of my deaths on Chroma are nuking an entire room and dying to combat discipline. (Bramma, Zarr, etc.)
Vex Armor: Bread and butter for Chroma. Hard disagree with the fact you can replace it with roar and serration. The fact that Vex Armor is one of the highest damage-increase abilities for weapons in the game (if built right) is a high point in itself. The only thing holding it back is trying to maximize Vex Armor. Most people won't run combat discipline and trying to find unCC'd enemies that shoot you before your teammates kill them all is like finding a chroma build that doesn't prioritize strength and duration. % damage reduction seems like an interesting idea for sure though.
Effigy: Hrodgrim forgot to talk about the credit booster that Effigy has, but Fred mentions it-
I hate that this is the ability that defines Chroma as meta in Profit-taker farms. Without it, there aren't many places where Chroma is used exclusively. Other than that, this ability needs a major change even if you give it separate mods. Why build and use Chroma for his fourth ability when Wukong can do it better and with cheaper mods as well? I also don't think that making his fourth ability pretty much like Wukong's clone is a good design choice too. I see Chroma as a weapon master, having a sentry that does not use your weapons seems like a lost opportunity, but we're basically cloning celestial twin at this point. Having the option to command it to sit and go seems as viable as Venari is to Khora's kit, and therefore will probably still remain as the subsume slot for Chroma if not for the credit booster. Effigy is such a weird ability because (I hate the fact that my Chroma looks like Xaku whenever I use it) it's such a core part of Chroma's original design and theme, that if it becomes anything else (other than a flying husk of a skin) you lose what makes Chroma special in the first place, even though it needs to change for people to be happy with Chroma. -Or just move/combine Effigy to his first ability or something idk.
Thanks for reading!
Edit: grammar mistakes
