Some comments in response to those made before:
* Regarding the alternate ending with swapping Marcus and John Connor, it would have good in that it would have been a real shocker, but if they had done it the producers would have painted themselves into a corner when the conclusion of the series (if they get that far) comes and Kyle Reese goes back in time. I mean, if it's not actually John Connor sending Kyle back, but Marcus, that would have destroyed the whole tragedy of the thing, wouldn't it? Although I did see enough hints of an interesting Reese-Marcus relationship in this movie that it could have had potential, but if they really want to tell the whole story, they're better off not killing Connor. Let's just hope Bale loosens up in the sequels!
I agree with the fans who disliked HBC being the one controlling SkyNet; her actual role in T4 as an avatar of SkyNet was almost passable. I hope in the future they actually do develop Skynet as a character. If they do, I'd like to see an AI villain that isn't just a cold human being (Agent Smith, the Architect, the Borg Queen?). Make it something really alien: intelligent, but with completely inhuman responses. We've got Terminators out the wazoo to blow up for the action component, but the man versus machine struggle is ultimately Connor v. SkyNet. I want to see that chess match, somehow.
T2 did good with the 'robot learning to be human' theme, but Arnold, God bless him, could only sell it so much. "I'm sorry John, I'm sorry."

As an actual actor in Worthington playing the machine appreciating what it is to be human, he did a much better than the guv. I do think on the other side, Edward Furlough did a better job showing how likewise a person could learn to love a machine/AI better than Blair, but it was close. Maybe the cut scenes would make a difference.