Yeah, the two clashing philosophies of T-2 and T-3 where painful. T-3 basically made the majority of T-2 pointless.

As for T-2 being unnecessary, I agree with CO, no sequel ever is really necessary, unless the first one was made with the intention of of a sequel and a cliff hanger ending (i.e. Lord of the Rings trilogy, Back to the Future 2 & 3, Empire Strikes Back and Return of the Jedi). But personally, I think T-2 makes T-1 a stonger movie. It adds more depth to it too me. I liked T1, but after T2 I promoted them both to "favorite movie" status, some thing I do not think I would have ever done with T1 alone. It was such a great follow up to te first movie. After something like the events of T1 happen in your life, how do you go back to a normal life? What do you do with yourself? How do you raise your kid? I think T2 does a great job at showing how Sarah went about these things, and how she nearly failed at them. What if your mom was this crazy nut job who through your whole like taught you about this inevitable coming war against the machines, and trained you how to be a soldier from the time you took your first steps?

These plot points are to good not to follow up on and make a story about. I also thought the tone of "the future being unwritten" was a great way to end the story.