If things starts to become like TERMINATOR then yes another war would break out if and ONLY IF the Synthetics takes the first shot. HOWEVER, after the events of ME3 and provided we take the path of Destroy as canon I AM 100% sure that no stupid Organics would want to try to re-create the same problem all over again. If they do decide to create synthetics they will have better preventive mechanism in place to prevent another war like what's that called? "LAWS AND SANCTIONS"
"ONLY IF the Synthetics take the first shot"
.....you mean like the Geth? Oh right. That didn't happen.
"I AM 100% sure that no stupid Organics would want to try to re-create the same problem all over again"
Because they tried to create it the first time around? Nope. But it happened. And even if some accidentally give birth to AI, Cerberus and Project Overlord have already proven that their will always be someone interested in purposely developing AI.
Not to mention, Shepard is the only soul who even knows the whole picture. He is the only being to discover the purpose of the cycles and the motivations of the Reapers. His knowledge does not apply to those people who are simply survivors of the war. They weren't up there. Kinda hard to prevent recreating a problem when you don't know what the problem is or are even aware that one exists.