Take the Worm timeline, and by authorial fiat, delay the arrival of the entities responsible for it all by about two decades. Rather than arriving in 1980, let them arrive on, say, September 10th, 2000.
Two or three days later, Second Impact occurs.
What with the fundamentally Different nature of the Angels (including First and Second), the entities completely failed to see this coming. They can't predict or detect the other Angels, either, except in the same ways humanity can.
This is going to considerably disrupt their plans.
(Take into account that Worm canon begins about 30 years after the entities' arrival, and that Evangelion begins about 15 years after Second Impact.)
Two or three days later, Second Impact occurs.
What with the fundamentally Different nature of the Angels (including First and Second), the entities completely failed to see this coming. They can't predict or detect the other Angels, either, except in the same ways humanity can.
This is going to considerably disrupt their plans.
(Take into account that Worm canon begins about 30 years after the entities' arrival, and that Evangelion begins about 15 years after Second Impact.)