Kain Steals the Dark Crystal vs. Mithos Is A Moron- No, no, the failure of the Kain scene is that despite being brainwashed, things like this make people hype Kain. The scene itself is whatever.
Partially true, but not quite.
The Kain failure comes from the fact that the team just STANDS THERE and does nothing to stop him. Kain doesn't exactly make a very effective exit either. He stands there for a good deal of time while Golbez rants (FF4 Original, mind, Golbez's little rant wasn't there; that was a DS addition which, in an attempt to explain things on the mind control, actually MADE THE SCENE WORSE), and Cecil and Co. just sort of gawk at it. And when he leaves, your team doesn't even do anything to chase him down either. Not to mention that he doesn't have an Airship or anything to leave promptly, or anything, so your team thinking "We'll never catch him!" logic is just stupid, ESPECIALLY when you have a freaking Ninja on your team trying to chase down a guy with Heavy Armor *OR* Mages who can immobilize the damn guy (FF4 has shown gameplay spells used out of battle A LOT, so this is one game where the Plot vs. Gameplay segregation excuse does not work, and part of why FF4 has so many dumb moments.) Now, I'm getting into a bit precise but...
The scene shows multiple opportunities to stop Kain, and your team manages to fail up every one of them. When he grabs it from Cecil, he's SURROUNDED by the entire team; you'd think one of them would try to, I dunno, grab him? Then he actually walks to the end of the screen, and sits there while Golbez rants. Your team does nothing to try and stop him, and then when he leaves, your team doesn't chase him down, despite having Mages who can immobilize it. The fact that people think this scene adds Depth to Kain when its just another "He's mind controlled, DAMN IT!" moment, and you have yourself a rather classic failure scene.
But what's also icing on it?
In the SNES version, I was able to suspend belief. Early SNES game, lower standards, etc., whatever, I can give it a bit of lenience there (not a lot though; FF4 was filled with cutscene stupidity all over the place, but lets not get into that.) By FF4DS though, a game that was actually altering some scenes here and there, "enhancing" the plot, etc., with far greater standards to work against now there's been several generations of upgrades since the original game?
I'm sorry, but here there's no excuse, and the fact that its in a modern remake that was changing some stuff makes it all the more insulting.
So basically, Fan Dumb + Classic Case of Cutscene Stupidity taken to a completely moronic level + They had the chance to fix it BUT DIDN'T in a "full" remake make for an atrocious scene.
The Manos, HAND OF FATE scene with Golbez fits too, except...
A. That scene is also hilarious in how its so bad. Its just so ridiculous that its funny (thus it fits into "Wrong" perfectly.) This scene, there's nothing remotely funny about it; its just your team being morons.
B. They did actually try to fix the scene in the DS Remake. The DS remake doesn't make the scene GOOD or anything, but at least upgrades it to "Eh, I can suspend belief and assume Golbez acted fast enough, while team was still recovering shock of 'HE'S STILL ALIVE?!?'" which while cheap and boring, its nothing particularly stand out one way or another.
Actually, B is another big reason the Kain scene fails. They fixed ONE scene, kind of, with immense amount of cutscene stupidity, why not another? Would it be so hard to, during Golbez's rant, have Edge try to charge Kain, only for a barrier Golbez created to block him (Kuja did something similar to Vivi in FF9, after all), to at least make it seem like your team ATTEMPTED to stop him. Yes, its cheap, boring, obnoxious, etc. but at least it removes Cutscene Stupidity from this scenes failure, and shows an attempt to fix it.
I'm not saying the scene is necessarily worse than the Mithos one; that one is dumb for completely different reasons, I'm just noting that you're underselling WHY the Kain scene is so bad. The Mithos one, naturally, is just a little more obvious as to why its such a retarded scene (I think just the name "Mithos" says everything.)