Mmm, I feel like rogues and hunters are actually the most "loner" classes of WoW tbh, it feels that way for me atleast. Survival is a loner surviving out in the woods, going all rambo on his opponents. BM relies on his pet and pet alone, marksmanship hunters shoot their opponents from a range, all we are is distraction basicly. Sub feels like survival, hiding out and striking at an opponents weak moment, taking it out quickly. Assasination is kinda the same but with the use of poisons (like poisoning someones food or w/e). Combat is probably the only spec I see that somewhat relies on his allies. But even a combat rogue would see his allies as disposable.
Like the discription rogues get (or used to get) in the character creation screen: "His loyalties only last as long as his contract" or something along those lines.