Why not both?

I agree with this one.

@Meh brony  
“ one death is a tragedy, a million is a statistic”

@Prometheus labs CEO  
Yep what makes psychopaths more terrifying and dangerous than sociopaths is how easily they can hide it and since they generally tend to aim for positions of power such as CEO of a large company they can do much more damage than a sociopath ever could, many of the most evil humans throughout history such as Stalin, a man who killed millions of his own people for power have many of the traits of psychopathy.

@Meh brony  
That’s about right, yes. it only makes it more disturbing to know there are people like that out there in the real world, and they are capable of emulating normalcy to a good enough extent

@Prometheus labs CEO  
I’d argue that’s She more of a Psychopath, someone who is completely unable to form personal bonds with others (she saw every pony as mere tool for her goals.), has zero sense of morality (she knew what she was doing could potentially destroy Equestria.) and feel no remorse for any wrongdoing they may have done (after being caught cozy didn’t even attempt to apologize even as she was being hauled away to Tartarus.) Sociopaths like starlight although struggle with empathy, morality and guilt are still capable of learning and understanding those concepts whereas psychopaths are completely unable to and thus can never truly change for the better.

She seems to be a textbook sociopath.  
Manipulative, lacking in empathy, incapable of telling right from wrong

This is a good thought.  
But completely wrong.

“She’s already shown to be quite manipulative, which doesn’t typically bode well for a character’s chances of being good in the end.”
 
Not really. This is one of the main traits in the Guile Hero trope.: http://tvtropes.org/pmwiki/pmwiki.php/Main/GuileHero
 
“Completing a triangle with the Action Hero and the Science Hero, the Guile Hero is a hero who operates by playing politics and manipulating the bad guys. The Guile Hero trades swords and guns (or science and technology) for charm, wit, political and/or financial acumen, and an in-depth knowledge of human nature. The Chain of Deals, along with the Social Engineering and Gambit Index tropes are all at the Guile Hero’s fingertips. Often, a Guile Hero will manipulate the other good guys and a whole bunch of innocent bystanders as part of his scheme to bring down the Big Bad, though he’ll take care to ensure the other characters aren’t truly harmed in the process (and if he fails, he’ll be very sorry). The Guile Hero is likely to be a politician or a businessman, and engage in Battles of Wits. If he has superpowers, then he’s likely to think that Heart Is an Awesome Power.”

So… Starlight Glimmer v2.0?

@zidders  
I didn’t really like Cozy Glow either, but she certainly wasn’t enough to ruin the episode for me. The Crusaders have been an absolute joy to watch this season, and they had some great moments this episode (the fake argument scene in particular was great).

@Cryosite  
Her voice acting is pure crocodile tears cheese. It is a poorly written episode that serves no other purpose besides being a setup for later episodes.

Honestly i hope that she’s the former, the latter is just way too predictable for me.

That’s what she wants you to think.

@Scrounge  
Going to bet everyone would

Then it’s weird that you don’t consider it kind of suspicious that her crying when she first appeared was obviously crocodile tears. She displayed zero issues with fake tears later, when she “failed”.
 
She’s already shown to be quite manipulative, which doesn’t typically bode well for a character’s chances of being good in the end.

@maze141  
She’s a marshmallow, just like her sister.

all I’m asking is: how can her hoof be so squishy? O_o

More people would probably think this if it weren’t for the leaked episode summaries.

Nope, I still believe she’s a villain that know how to act infront of everyone.
 
If you want to reach your goal, you have to be patience and start from the bottom building trust between people/pony until they really believe in you. Then when the time is right and have enough information about everything you want to know, that’s is the time where you attack.
 
In order to defeat your enemy, you must know them. Their strenght, their weaknesses, their friends and family, their time in the school, the school layout and etc.

@Background Pony #E2E6  
But that would make the episode poorly written, while the thing the OP is posting would simply make for good characterization. Good writing instead of dumb writing.
 
Having her be a generally good person also sets things up for later episodes. She can become a friend with interesting things to do and might be helpful against whoever the future antagonists are.

@archestereo  
It would at least be setup to something bigger in another episode.

@Background Pony #E2E6
 
…okay, but how does a secretly evil Cozy Glow change that?

Then it would make that last episode feel very poorly written.

Nonsense! Preposterous! You lunatic!