She doesn't need to "go bad" - just uncertain. If she has her own goals, John has to figure out whether they're justified or not. If she wants to survive and hide in human society, and stop Skynet from ever existing, I'd say John probably wouldn't have that much a problem with that. Sarah and Derek would have a problem, but not John.
Making Cameron independent allows you to view her as any other character, i.e., you don't know what she'll do. If she has her own goals, sometimes they may conflict with the other characters, sometimes they won't. We can see that to some degree now with the issue of Riley. In this situation, Cameron's desires conflict with John's, but in fact Cameron is correct to suspect Riley. In some other situation, Cameron may be wrong in her approach, but not know it.
If Cameron's overall goal is to survive, we could see that part being realized over time, but her subsidiary goal of seducing John Connor might not succeed - and might not have to. Cameron may be assuming she has to follow that path, but it probably would be better for her merely to tell John what she wants. As I indicated, I think John would allow her to be independent and pursue her goals as long as they don't end up harming humans. But as an infiltrator, she tends to operate clandestinely - which could hurt her achieving her goals in the long run.
You could stretch out a series for a long time based on that sort of dynamic without ever having her have to actually "go bad"
I agree that the "suddenly going evil" bit is commonplace. They even did that on "Highlander" one time - they ran a one or two part story where Duncan McCleod was overwhelmed by the personalities he absorbed from evil Immortals and he became evil
I think the TSCC writers might be aware of this problem. The speech Catherine Weaver gave about not finding evil in Terminators might indicate a more nuanced approach to this.
At the same time Weaver seems to be one of the few Terminators we've seen who really seems to enjoy killing humans. Cromartie responded to Sarah's "I'm not a murderer" by saying "Who is?" I don't think Weaver would have responded that way. Cromartie was slick and clever and a liar but he seemed mostly unemotional in killing humans, as was Vic. Weaver seems "twisted", to use Derek's phrase.
Cameron's original nature in "Allison From Palmdale" seemed closer to Weaver than Cromartie, but it's hard to tell.
It may merely be a distinction in terms of how more advanced they are in how they emulate human behavior. In short, the more "evil" they seem, it may merely be because they seem more human in their expression of their intentions.
In any event, while Cameron can become more able to respond in a human fashion to circumstances, the writers should continue to make a clear distinction between her being an AI and her ability to simulate human behavior. They should not blur the line too much. So far I think they've done this fairly well. It's the fans who are seeing more "humanity" in Cameron than is actually being "written in" by the writers.
Whatever they do, I hope they don't overuse the "glitch" stuff. That should be retired, it's done it's job. In fact, I'd appreciate retiring the "am I going to go bad" worrying Cameron has been doing - that's getting old, too. Cameron can be given problems without being a dysfunctional character at her core.
Of course, what's irritating about the show now is that is precisely the problem with the "heroes" - they're all so dysfunctional that I'm starting to lose interest in them as "heroes". If I wanted to see losers saving the world, I'd watch "Cheers".
I wouldn't mind the odd screwup or failure, nobody's perfect (they even made Daniel Craig's James Bond less than perfect, which has been great) but this is getting ridiculous.
I was just watching season one over again last night. In episode 9, John talks about his birthday not being important and what is important is finding "The Turk" and stopping Skynet, and Sarah tells him his life is important - and then in season two, all that was reversed. Sarah won't let John date, and they've all completely forgotten about "The Turk".
If you want to talk about people "going bad", I'd say in season two the Connor Team pretty much ALL "went bad". Cameron glitched, John became a rebel, Sarah went nuts, and Derek got suckered by his ebil girlfriend into a dumb plot to off Cameron. And of course, Ellison became an idiot, which, however, wasn't much of a change from his season one nature.
I hope they intend to at least partially reverse again all this stuff, and give us back the flawed but basically intelligent people we had in season one. Please, please, get rid of the "idiocy".