Yeah, I had a hard about-face on how I thought of Vriska here.
What would make Vriska better: With current Vriska, she is trying to ease the guilt she feels for losing her friends, or at the very least trying to get her group back together. So I think she is on the right track, albeit with somewhat selfish desires. To make her better she would have to feel remorse over paralyzing Tavros. I get that she kills trolls to feed spiders, Terezi wasn’t innocent in that either, and it was based on survival, so that gets a pass. But to actually understand what she did, and apologize to him.
What would make Vriska worse: betrayal would be up there. She was/is very easily manipulated by both Scratch and Terezi. If she just decides to fuck them over or just fuck the game over to screw with them on purpose, yeah that would be bad. If she somehow turns on her friends again in a fit of rage, that would be some bad points. Especially if she attacks Terezi and almost kills her. I can see a possibility of them meeting up in game, getting into a huge argument, and having Vriska control Terezi to the point of almost death. Yeah, that would be shit.