Re: Timeline branching going forward *spoilers*
The post-'First Contact' had a Zephram Cochrane that talked about killer zombie cyborgs in the future.
And how do you know the pre-FC didn't also include that? As has been said before, it could be a predestination paradox. Meaning, there was never a timeline when it did not happen. You can't prove that this was not the case.
"If the world was perfect, it wouldn't be." - Yogi Berra