Are you saying that the sequels could have been made with no John Connor in them?
Could a sequel have been made with Sarah Connor in it with no John Connor?
Nobody says it should've been made with no John Connor, what I'm saying is that it should've been made without a kid. Not the same thing.
Though now that you mention it, I'd have liked to see a desperate war of Connor-less humanity against the machines even more than I would've liked to see a T2 with an adult John Connor. It would go perfectly with T2's "no fate but what we make" theme. We have no John Connor, but we win anyway. That would've been awesome.
Oh, and one other thing: The time travel gimmick was acceptable once
. Building a film on it the second time is just asking too much in terms of suspension of disbelief, at least for me.