Actually, Kyle Reese no longer has to get sent back in time, since the time-lines have all been altered since T1... Kyle only had to be sent back from T0, time-line ZERO, the original time-line, to save Sarah Connor... Kyle was not John Connor's original father, but Sarah was too confused and caught up in the whole time-travel, alternate time-line thing to really make sense of it..
Remember that guy who broke his date plans with Sarah earlier that night? he left a message that he was stuck working, so he couldn't make it, so Sarah left to see a movie while Ginger and Matt stayed home and screwed... in the original time-line, that guy might have made a second date with Sarah later that week or sometime soon after. So that guy, whoever he was, could have been John Connor's dad originally... once Kyle and the Terminator came back and altered the course of Sarah's life so drastically, making her the mother of the future and all that crap, she never got a chance to date John's original dad, but the seed had already been planted, in more ways than one, by Kyle, who her son was destined to be... so she 'made' Kyle's baby into John Connor any way, and changed the future just a bit, and then she and the new John went on altering future time-lines in T2...
now that T3 has happened, once more altering the time-line, its no longer a given that John will even meet Kyle, maybe Kyle doesn't exist in the new time line because of some weird aberration from the few alterations in the new time-lines?? If there's no more time travel, no more alternate time lines, then the T3 time-line can play out in any number of ways, including the extinction of all mankind... or the complete conquering of the machines and destruction of SkyNet... it could go any number of ways, and still complete the story of the new, altered time-line...
in some ways, having the story come to and end, rather than forcing the loop, might even be better, because it could mean more and more and more awful/awesome sequels and the debates which follow...
Personally, I hope to see the loop closed, Connor does meet Kyle and sends him back, knowing that because he sends him back all the alterations happen in T1, T2, and T3, in order to lead to him sending Kyle back.. but because of the theory of chaos, it doesn't necessarily have to happen that way...
so, any way, the point relevant to this thread is that Michael Biehn may not need to be called upon to reprise his role as Reese... see?
OOOOOOhhh yeah! What if all along, Kyle was Kate and John's kid!! Then, Kate and John get busted out of the Crystal Peak bunker by -GULP!- a Death Camp Squadron of Flying H/Ks, Kate and the baby are taken away and John is targeted for termination as the Future Leader of the resistance. Luckily, in their spare time under Crystal Peak, John and Kate rebuilt the TX-850 so the anti-Terminator terminator (which now can look like Arnold, or Kristanna, or anyone really!!) busts John out, but John is separated and devestated by not being able to get Kate and the baby out... so he has to organize the rag-tag reistance from the few others who were freed from the camp when TX-850 stormed the place... They save Kate, but not the baby... awwww! 🙁
Thats OK, they can save the baby and the future in T5... and they try to do just that, only lots of stuff happens to keep them away, for about 20 years... when they finally are reunited with the Baby, he has grown, and has taken the name Kyle Reese!!! John about has a fit when he realizes that his son may be his father... but no time for brain embolysms, because the machines are kicking ass again!
the resistance is about to all be wasted when Sarah Connor comes racing in to save the day, with help from Mr E Mann, the dude who dumped her in T1, who then hid her out, off the grid and gathered forces for the resistance... John gets very badly injured in the escape this time, and only a blood transfusion will save him. Unfortunately, no one is a suitable match, except tada! Mr E Mann, the loser who dumped Sarah in T1! Turns out that was the second date he had to cancel, and he really was hurt by cancelling because SArah was such a good lay that first time!! So, John was NOT Kyle's kid after all, therefore Kyle can go back still and save the future, but this time around, John makes sure to slip Kyle some condoms, just to be safe!! 😉
GENIUS! Of course, by the end of T5:As the Machine-Dominated World Turns ends, everyone will be fed up completely with the road the franchise has taken, so finally the Terminator saga will end, the loops will close and everyone will live happily ever after!!