I'm pretty sure you can still melee the nullifier inside his own bubble, the problem with it killing hysteria is solved by simply waiting until the timer nearly runs out. At that point, you just charge into the bubble, melee the guy to death, then run off to pop Hysteria back on.

Except for the part where you get gunned down by Heavy Gunners/Bombards/what have you. Sure is great being the tankiest frame in the game amirite? :/

Additionally, you're ignoring some possibilities from other frames that indirectly buff allies to do what they do only better. Mirage, for instance? Hall of Mirrors + Hall of Malovence is purely a self-damage buff for every enemy killed while the power is active. Since your guns put out more DPS than Sayrn's ultimate, and it's a stacking buff for every single enemy downed, that's fairly significant in DPS. Additionally, her secondary is admittedly very situational but used correctly can be devestating when you turn all the enemy defense fortifications AGAINST them and you render the door lasers/barriers useless against you for a little while. Finally, her third power - Eclipse - has a mod that grants it to EVERYONE on the team.

And then Resonating Sonar became a thing and allowed you to stack Sonar spots on the same spot for a multiplicative damage bonus. Which is dumb. As soon as that came out, Mirage got dropped from the top tier. Everything else is mediocre. This is dumb and bad. Nuke frames have been effectively removed from the game since Damage 2.0 has been a thing. This sea horse frame is going to be in the same boat. Gimmicky and ultimately terrible. Even Mesa has damn good crowd control. That should tell us something.

And then there's Oberon, who has a good range of powers between healing to limited CC through Retribution, or Nekros who can both insta-revive players with soul punch augment and, for defense missions, actually make use of Terrify because while the enemies are running away from you, they're also running from the objective.

But why Terrify when you can M.Prime, Irradiating Disarm, Vortex, Bastille, etc? Terrify wastes everyone's time. The other abilities do not. That's the problem. Why take Oberon when Trinity has always existed with flat out better powers? Nekros is only good for Survival oxygen drops. We all knew that.

I think what you're trying to argue has to do with the idea that anything that isn't dedicated CC and/or can be used for the most efficient manner of CC is not viable in the end-game. But at the same time, you seem to have no value for powers that are very much great utility powers only because you don't see anything not-CC related as being worth the time to use.

Because they don't scale at all. They simply don't. A dude knocked down at level 1 is the same at level 100. Miasma will kill the guy at level 1 but at level 100 won't even notice.