T2: We can change the future. T3: Kinda, but you're wrong. To like the ending of T2 you have to ignore the fact that if they stopped judgement day, then there would be no reason to send Kyle back to save John's mom from the first terminator. Thus; ending his existence a la Back to the Future. (That's not to say that I am an expert on time travel, for the timeline had already been altered, thus taking it in another direction without being erased... parallel timelines come into play there though, but I'm going with the simplest explaination.)
Lame cliches and sight gags? T2 had plenty, I suggest you go back and watch again. T2 didn't really have any darker a story than T3, it the most touchy feely of the Terminator movies. I thought T3 was wonderful for being more related to the roots of the series. As for John Connor being a whiney sissy, he just didn't want the future that was ascribed to him. I think he summed it up pretty well, by saying that in order for him to do the greatest thing ever for humanity, he'd have to let something terrible happen. You also see that he does take up his responsibility in the end of T3 when he picks up that radio. See, that's called character development...
Oh come on, you can boil anything down like that. T2 had some shiny cg and arnold with a minigun, and that's about it. But see, both of those statements sell the films short. They're both excellent movies and I for one love them both dearly.
I'm not trying to get to to change your opinion, but perhaps some elements needed clarification for you. But to each his own.
As for Terminator 4, I don't think they even need Arnold anymore. They could just do the war in the future and have a bunch of endoskeletons running around. I really hope they do this because I would LOVE to have the series come full circle.