Think of it. A three part movie series.

The first one is very cryptic on what’s happening. You follow a ragtag group through a war-torn wasteland trying their hardest to survive an enemy that’s never actually seen on screen. And only at the very end do you meet John Connor, the brilliant tactician, and the first on-screen T-101.
Don’t even CALL it Terminator. Have it be a total surprise to the audience.

In the second one you take the ragtag group you followed in the first movie, and have them fight alongside John to his untimely death, learning to be like him the entire way. He explains his past, his plan, and his reputation, and has them all promise to follow through. The movie ends with the group splitting up to find and unify the human army.

The third is the final fight. Everything was leading up to this. The once disjoint human army is now unified and working synchronously. Skynet can’t keep up from this dramatic turn of events and through the movie we follow it figuring out that the problem is “John Connor”.
It turns it’s time machines (created initially to reverse the recent human retaliation due to it’s complexity) to eradicating the entity known as John Connor from existence. But because John was trained from a young age, he’s stayed off the radar and Skynet gets little more than the name of his mother.
Skynet sends it’s most advanced machine to eradicate John, but it is unable to send it back far enough.
Skynet spends some more time and more power and is able to send back a T-1000 , only to find the time portal malfunctioned and didn’t send him back far enough.
After a final recalculation, Skynet successfully sends a T-101 back to the proper time just as ‘John’ wins the war.
‘John’ enters the portal room (or sees it) just as the T-101 moves though, and immediately knows what just happened.
Movie end.

Not really. Given that John Connor’s been played by a different actor in every movie so far, who cares about replacing him? It worked with Doctor Who…

Secondly, I kinda thought they should have killed John Connor in the third movie, perhaps by having him realize that he is, in some way, the result of a paradoxical causality loop that links his theoretically impossible existence with Skynet’s, and so the only way to permanently destroy Skynet is to die as well, closing the loop and repairing the timeline. After all, Skynet’s existence is directly responsible for Connor’s birth (without Skynet, there never would have been a reason to send back Reese), and Connor’s existence was one of the principle factors in Skynet’s inception (the arm and the chip from T2 opening the doors to new avenues of research for Cyberdyne). They’re both temporal anomolies! I read a great fan script (I usually don’t, but it was a good one) that theorized that it was mankind experimenting with time travel in the 2000s that accidentally created the temporal loophole that allowed Skynet and Connor to exist in the first place, and I think it’s a clever, logical explanation for what is essentially just a continuity nightmare. The script was called Tempest: Terminator 3, and if you ever get a chance to read it, I recommend it highly (it also featured Arnold as Skynet itself, downloaded into a Terminator endo and sent into the past, where he dresses in Armani and drives a Ferrari. He later trades up for a general’s uniform and a humvee, har har).

Finally, I don’t know if anyone mantioned this (I didn’t read all the comments), but the original ending to Terminator: Salvation was kinda similar to this, in a way. Unfortunately, it was infinitely less plausible: Connor dies after having a metal pike driven through his chest (which you’d think would be a given), but everyone knows that his name and legacy are invaluable to the Resistance… so they GRAFT HIS FACE onto Marcus Wright, and Marcus becomes the new John Connor. This idea was unbelievably stupid, not least because because Sam Worthington’s bone structure is so vastly different from Christian Bale’s, but at least it showed a spark of originality- and it even explained why Marcus, not John, is clearly the main character in that movie! But I guess the idea was a little too extreme for Warner Bros., so they dumped it in favor of guerilla heart surgery… which, honestly, I can’t decide which one’s more implausible.

Secondly, I kinda thought they should have killed John Connor in the third movie, perhaps by having him realize that he is, in some way, the result of a paradoxical causality loop that links his theoretically impossible existence with Skynet's, and so the only way to permanently destroy Skynet is to die as well, closing the loop and repairing the timeline. After all, Skynet's existence is directly responsible for Connor's birth (without Skynet, there never would have been a reason to send back Reese), and Connor's existence was one of the principle factors in Skynet's inception (the arm and the chip from T2 opening the doors to new avenues of research for Cyberdyne). They're both temporal anomolies! I read a great fan script (I usually don't, but it was a good one) that theorized that it was mankind experimenting with time travel in the 2000s that accidentally created the temporal loophole that allowed Skynet and Connor to exist in the first place, and I think it's a clever, logical explanation for what is essentially just a continuity nightmare. The script was called Tempest: Terminator 3, and if you ever get a chance to read it, I recommend it highly (it also featured Arnold as Skynet itself, downloaded into a Terminator endo and sent into the past, where he dresses in Armani and drives a Ferrari. He later trades up for a general's uniform and a humvee, har har).

Finally, I don't know if anyone mantioned this (I didn't read all the comments), but the original ending to Terminator: Salvation was kinda similar to this, in a way. Unfortunately, it was infinitely less plausible: Connor dies after having a metal pike driven through his chest (which you'd think would be a given), but everyone knows that his name and legacy are invaluable to the Resistance… so they GRAFT HIS FACE onto Marcus Wright, and Marcus becomes the new John Connor. This idea was unbelievably stupid, not least because because Sam Worthington's bone structure is so vastly different from Christian Bale's, but at least it showed a spark of originality- and it even explained why Marcus, not John, is clearly the main character in that movie! But I guess the idea was a little too extreme for Warner Bros., so they dumped it in favor of guerilla heart surgery… which, honestly, I can't decide which one's more implausible.

But a few days ago I re watched the series because i wanted to understand where exactly should they have taken a different direction…
I realized its not that bad that he isn't really like a Vietnamese war hero who cut trough the jungle alone and took out half of the Viet Kong with his eyes closed and both hands tied back.
Actually it hit me during the beginning-ish scene in T3 where they are traveling in a van with Mrs. Connor in the back. And Johnny notices a strange coincidence about the Terminator's sudden appearance (not sure what it was exactly).

For just a second imagine if him being the chosen one was not 'simply' about being something of a war hero, if that was only a wake up call for HQ… What if his real ability was see patterns coincidences in happenings? Skynet is a computer it is programed mathematically, so to some depth every movement it makes follows a complex pattern. What if he can predict Skynets next movements even when HQ fails to do so? That would be something to fear from Skynet's side wouldn't it?